OIL  ENGINES 


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First  Diesel  built  in  the  United  States — 1898. 


(Frontispiece) 


OIL  ENGINES 


DETAILS  AND   OPERATION 


BY 

LACEY  H.  MORRISON 


FIRST  EDITION 


McGRAW-HILL  BOOK  COMPANY,  INC. 
239  WEST  39TH  STREET.    NEW  YORK 


LONDON:  HILL  PUBLISHING  CO.,  LTD. 

6  &  8  BOUVERIE  ST.,  B.C. 

1919 


.bugineering 
Library 


COPYRIGHT,  1919,  BY  THE 
McGRAW-HiLi  BOOK  COMPANY,  INC. 


THR     MAl>l.B     PKKSS     T  O  K  K     PA 


PREFACE 

This  volume  has  been  written  with  the  idea  of  providing  oil 
engine  operators  with  information  as  to  the  details  of  construc- 
tion and  methods  of  adjustments  of  the  more  important  oil 
engines  manufactured  in  the  United  States. 

The  author  wishes  to  express  his  thanks  to  those  manufacturers 
who  kindly  supplied  drawings  and  photographs  of  various  engine 
parts. 

L.  H.  M. 

PHILADELPHIA,  PENNA. 
July,  1919. 


CONTENTS 

PAGE 
PREFACE vii 

CHAPTER  I 

HISTORICAL 1 

General — Huyghens — Barber — Lenoir — Otto — Beau  De  Rochas 
Otto  Silent — Bray  ton  —  Hornsby- Ackroyd  —  D  i  e  s  e  1 — Diesel 
Marine  Engines. 

CHAPTER  II 

THE  DIESEL  ENGINE 10 

Cycle  of  Events — Schematic  Layout  of  Diesel  Engine — American 
Diesel — Busch-Sulzer — Mclntosh  &  Seymour — Snow — Allis- 
Chalmers — National  Transit — McEwen — De  La  Vergne— Two- 
Stroke-Cycle — Southwark-Harris — Standard  Fuel  Oil— N  o  b  e  1 
Bros.  Marine — Werkspoor  Marine— Mclntosh  &  Seymour 
Marine — Fulton  Machine  Co.  Marine — Lyons-Atlas — Nordberg. 

CHAPTER  III 

INSTALLATION  OF  AN  OIL  ENGINE 32 

General — Excavation — Establishing  Engine  Center  Line — 
Engine  Template — Foundation  Material — Foundation  Bolts — 
Insufficient  Foundation — Vibration — Installation  of  Engine 
Frame — Leveling  up  Frame — Erecting  the  Cylinders — Centering 
the  Shaft— Plant  Building. 

CHAPTER  IV 

MAIN  BEARINGS 44 

Adjustable  Bearings,  Vertical  Engines — Adjustable  Bearings, 
Horizontal  Engines — National  Transit — Snow — Allis-Chalmers 
— Two  Piece  Bearings — Mclntosh  &  Seymour — Busch-Sulzer — 
McEwen — De  La  Vergne — Aligning  Bearings — Hot  Bearings — 
Scored  Shafts — Fractured  Crankshafts — Hot  Bearings,  Two- 
Stroke-Cycle  Engine. 

CHAPTER  V 

CONNECTING  RODS 57 

General  —  American —  Allis-Chalmer  s — Snow — McEwan — 
Mclntosh  &  Seymour — National  Transit — Busch-Sulzer — 
De  La  Vergne — Nelseco — Big  End  Bearings — Pin  Clearance. 

ix 


x  CONTENTS 

CHAPTER  VI 

PAGE 

PISTON  AND  PISTON  PINS 64 

General— Trunk  Pistons — Piston  Clearance— Crosshead  Type 
Piston — American  Diesel — Busch-Sulzer  Type  B — Mclntosh  & 
Seymour — Allis-Chalmers— McEwen — Snow —  Standard  Fuel 
Oil— Siezed  Pistons— Piston  Wear— Piston  Rings— Fractured 
Piston  Heads— Piston  Ring  Troubles— Grinding  Taper  Pin 
Bosses — Worm  Piston  Bosses — Emergency  Piston  Pins. 

CHAPTER  VII 

CYLINDERS  AND  CYLINDER  HEADS 79 

General — American  Diesel— Standard  Fuel  Oil— Busch-Sulzer — 
A  Frame  Cylinders— Horizontal  Diesel — Snow — De  La  Vergne — 
McEwen— Allis-Chalmers — National  Transit — Fractured  Cyl- 
inders— Scored  Cylinders— Liner  Replacement— Cylinder  and 
Head  Joint— Cylinder  Stud  Bolts — Fractured  Heads. 

CHAPTER  VIII 

DIESEL  ADMISSION  AND  EXHAUST  VALVES.    .    . 93 

General — Valve  Mechanism — American  Diesel — Adjustments — 
Timing— Busch-Sulzer  Type  B — Adjustments — Cam  Levers — 
Cam  Clearance — Valve  Timing — Cam  Shaft  Layout — Mcln- 
tosh &  Seymour — Camshaft — Cam  Clearance — Valve  Timing 
— Snow — Camshaft — Cam  Clearance — McEwan — Camshaft — 
Cam  Clearance — Valve  Timing — National  Transit — Valve  Cam 
Mechanism  —  National  Transit  1918  Design  —  Camshaft — 
Timing— Allis-Chalmers  — Camshaft  — Standard  Fuel  Oil- 
General — Timing — Mclntosh  &  Seymour  Marine  Diesel — 
Rockers — Reverse  Control — Nelseco  Marine  Diesel  Rockers — 
General —  Valve  Cages  —  Water-cooled  Valves  —  Corrosion  — 
Cleaning  Valves — Grinding  Valve — Valve  Grinding — Valve 
Timing — Leaky  Valves. 

CHAPTER  IX 

DIESEL  FUEL  INJECTION  VALVES 127 

Dr.  Diesel's  Original  Injection  Valve — Injection  Action — Open- 
Nozzle  Valves — Closed-Nozzle  Valves — American  Diesel — 
Adjustments  —  Busch-Sulzer  —  Adjustments  —  Rocker  Mechan- 
ism— Servomotor — Mclntosh  &  Seymour — Action — Adjustments 
— Starting  Fuel — Mclntosh  &  Seymour  Marine  Diesel — Snow 
—Adjustments— Korting—  McEwen  — Adjustment  s— Allis- 
Chalmers — Adjustments  —  National  Transit  —  Adjustments — 
Standard  Fuel  Oil— Adjustments— Fulton  Marine— Nelseco 
Marine— General — Tar  Oil  Fuel  Valves— Regrinding  Valves- 
Needle  Valves— Leaky  Valves — Valve  Timing — Injection  Air 
Pressure— Adjustable  Timing— Timing — Back  Lash. 


CONTENTS  xi 

CHAPTER  X 

PAGE 

DIESEL  FUEL  PUMP 159 

General — American  Diesel  —  Ad j ustments — P  u  m  p  Valve  s — 
Busch-Sulzer  Type  B  Diesel — Adjustments — Timing — Mclntosh 
&  Seymour — Original  Fuel  Pump — Present  Fuel  Pump  — 
Mclntosh  &  Seymour  Marine  Diesel — Adjustments — McEwen — 
Adjustments  —  Snow  —  Adjustments  —  Allis-Chlamers —  DeLa 
Vergne  Type  F  D  —  Nelseco  Marine  —  Adjustments — National 
Transit — Adjustments — National  Transit  1918  Fuel  Pump — • 
Standard  Fuel  Oil  —  Adjustments — General  —  Pump  Valve 
Grinding. 

CHAPTER  XI 

GOVERNORS,   DIESEL .     181 

General  —  American  Diesel  —  Ad  j  ustments  — S  ysten  Jahns 
Governors — Regulator — Busch-Sulzer  Type  B — Snow — National 
Transit  —  McEwen  —  Allis-Chalmers—  Standard  Fuel  Oil — 
Mclntosh  &  Seymour — Eccentric  Positions — General  Adjust- 
ments— Governor  Springs — Governor  Drive  Shafts — Gear 
Lubrication. 

CHAPTER  XII 

AIR  COMPRESSOR  SYSTEMS,  DIESEL 195 

General — Compressor  Stages — Air  .  Systems — Independent 
Compressor — Built-in  Compressor — Busch-Sulzer — Air  Regula- 
tion— Mclntosh  &  Seymour  Marine  Diesel — Stationary  Diesel 
Compressor — Snow — McEwen — National  T  r  a  n  s  i  t — Standard 
Fuel  Oil  —  Allis-Chalmers — General — Valves — Lubrication — Air 
Piping — Air  Bottles — Air  Pressure. 

CHAPTER  XIII 

COOLING  SYSTEMS,  DIESEL 209 

Distribution  of  Heat  Losses — Cooling  Water  Required — Types  of 
Cooling  Systems — Closed  System — Open  System — Water  Piping 
— Water  Tanks  and  Towers — Regulating  Float — Cooling  Towers 
— Circulating  Pumps — Bad  Water — Water  Purification — Sediment 
— Salts — Exhaust  Distiller — Cooling  Water  Temperature. 

CHAPTER  XIV 

LUBRICATION,  DIESEL 224 

General — Lubricator  System — Mechanical  Lubricators — Stream 
Lubrication — P  r  e  s  s  u  r  e  Feed — Busch-Sulz  er  System — Water 
Separator — Splash  Oiling  System — Lubrication  Oil  Require- 
ments— Lubrication  Oil  Specifications — Amount  of  Lubrication. 


xii  CONTENTS 

CHAPTER  XV 

PAGE 

DIESEL  FUEL  OILS 232 

Combustion— Fuel  Classification— Stove  Oil— Solar  Oil— Fuel 
Oil— Gas  Oil— Diesel  Oil— Desulphurized  Oil— Distillate  Oil- 
Tops— Crude  Oil— Specifications— Heat  Value  of  Oils- 
Gravity — Residue — Flashpoint — Burning  P  o  i  n  t — S  u  1  p  h  u  r — 
Water-Ash—Viscosity — Acid — Engine  Oil  Tanks — Oil  Storage 
Tanks— Coal  Tar  Oils— Method  of  Burning  Tar  Oils. 

CHAPTER  XVI 

FUEL  CONSUMPTION,  DIESEL 251 

Guarantees— Tests — Snow — McEwen — Standard  Fuel  Oil— 
Korting — Busch-Sulzer — Mclntosh  &  Seymour — Sulzer  Bros — 
Actual  Operating  Results — Production  Costs — Gas  Engine  Plants 
— Producer  Engine — Comparative  Costs — Steam  vs.  Diesel — 
Plant  Logs — Heat  Balance — Indicator  Cards — McEwen  Indicator 
Cards — Allis-Chalmers  Indicator  Cards — National  Transit  Indi- 
cator Cards — Standard  Fuel  Oil — Faulty  Cards — Distorted 
Cards — Indicator  Rigging. 


CHAPTER  XVII 

THE  SEMI-DIESEL  OIL  ENGINE 280 

General — Comparative  Indicator  Cards — Ignition  Devices — 
Hvid  or  Brons — St.  Mary's —  Operation — Modified  Hvid — 
Lyons-Atlas — Burn  Oil — Nordberg — Mtiller — De  La  Vergne 
Type  F  H— Fuel  Consumption — Fuel — Price  Ignition  System- 
Indicator  Cards— Test. 


CHAPTER  XVIII 

LOW-COMPRESSION  OIL  ENGINE 306 

General — Two-Stroke-Cycle,  Operation — Theory  of  Combus- 
tion —  Ignition  Devices :  Hot-Bulb— Hot-Bolt— Hot-P  late  — 
Separate  Combustion  Chamber — Operation — De  La  Vergne. 


CHAPTER  XIX 

LOW-COMPRESSION  ENGINE  CYLINDERS 324 

Cylinder  Design— Two-Cycle — Crank  Case  Compression 
Cylinder — Cylinder  Using  Front  End  For  Compressor — Cylinder 
With  Removable  Liner — Vertical  Engine  Cylinder — Cylinder 
Wall  Thickness— Reboring  Cylinder— Cylinder  Wear— Fractured 
Cylinders— Cylinder  Head  Packing. 


CONTENTS  xiii 

CHAPTER  XX 

PAGE 

PISTONS,  PISTON  PINS  AND  CONNECTING-RODS,  Low  COMPRESSION 

ENGINE 333 

Pistons,  Types — Clearances — Turning  New  Pistons — Distorted 
Pistons — Piston  Rings — Distorted  Exhaust  Bridges — Fractured 
Piston  Heads — Piston  Pins — Connecting  Rods — Adjustments — 
Babbitting  Crank  Bearings — Crank  Pin  Clearances — Pin 
Lubrication. 

CHAPTER  XXI 

FRAMES,  BEARINGS,  SHAFTS  AND  FLYWHEELS;  Low  COMPRESSION  OIL 

ENGINE 347 

Engine  Frames — Inclosed  Frames,  Open  Frames — Air-Suction 
Valves;  Automatic — Piston  Air  Valve — Corliss  Air  Valve — Ad- 
justments— Crankshaft  Air  Seals — Main  Bearings — Adjustments — 
Crankshaft — Flywheels . 

CHAPTER  XXII 

GOVERNORS,  FUEL  INJECTION  PUMP,  Low  COMPRESSION  ENGINE  .  .  .  365 
Governors;  General — Hit  and  Miss  Governing — Classes  of 
Governors — Muncie  Governor — Muncie  Fuel  Injection  Pump — 
Adjustments — Fairbanks- Morse  Horizontal  Engine;  Governor — 
Fuel  Pump — Fairbanks-Morse  Vertical  Type  Y;  Governor — Fuel 
Pump — Adjustments — Mietz  &  Weiss  Horizontal  Engine; 
Governor — Fuel  Pump — Mietz  &  Weiss  Vertical  Engine; 
Governor — Fuel  Pump — Fuel  Destributor — Adjustments — Fuel 
Timing  Control — Little  Giant;  Governor — Fuel  Pump — Gover- 
nors Giving  Constant  Injection  Angle — Bessemer  Oil  Engine; 
Governor — Fuel  Pump — Adjustments — Primm  Oil  Engine; 
Governor — Fuel  Pump — De  La  Vergne;  Governor — Fuel  Pump — 
Buckeye-Barrett  Oil  Engine;  Governor — Fuel  Pump. 

CHAPTER  XXIII 

FUEL  NOZZLES;  WATER  INJECTION;  Low  COMPRESSION  ENGINE  .  .  .  403 
Fuel  Nozzles — Little  Giant  Fuel  Nozzle — Muncie  Fuel  Nozzle — 
Fairbanks- Morse  Fuel  Nozzle — Buckeye-Barrett  Fuel  Nozzle — 
Primm  Fuel  Nozzle — Bessemer  Fuel  Nozzle — Mietz  &  Weiss 
Fuel  Nozzle — Care  of  Fuel  Nozzle — Water  Injection — Cylinder 
Wear  Due  to  Water  Injection — Faulty  Lubrication  Caused  by 
Water  Injection — Method  of  Injection — Bleeder  Valve — Muncie 
System — Mietz  &  Weiss  System — Primm  System — Little  Giant 
System — Bessemer  System — Engines  Without  Water  Injection — 
General — Manipulation  of  the  Water  Injection. 


xiv  CONTENTS 

CHAPTER  XXIV 

PAGE 

EXHAUST  PIPE  AND  PIT  ./ATER  COOLING  SYSTEMS,  LOW-COMPRESSION 

ENGINE 420 

Exhaust  Pipes — Exhaust  Pits — Circulating  Water  Systems— 
Thermo-Syphon  System — Fresh  Water  System — Tank  and 
Tower  System — Closed  System. 

CHAPTER  XXV 

AIR  STARTING  SYSTEMS,  OPERATING  TROUBLES,  LOW-COMPRESSION 

ENGINE 432 

Air-Starting  Systems — Fairbanks- Morse  Air  Starting  Valve — 
Primm  Air-Starters — Mietz  &  Weiss  Air  Starters — Starting  an 
Engine — Temperature  of  Cooling  Water — Lubrication — Engine 
Smokes — Preignition — Engine  Pounds — Indicator  Cards — General. 

CHAPTER  XXVI 

FUEL,  FUEL  CONSUMPTION,  LOW-COMPRESSION  ENGINE 447 

Fuel — Fuel  Specifications — Engine  Behavior  On  Various  Oils — 
Fuel  Storage — Fuel  Consumption — Tests — Operation  Costs — 
Conclusion. 

INDEX  .  461 


OIL  ENGINES 


CHAPTER  I 
HISTORICAL 

Although  for  decades  the  internal  combustion  engine  was 
neglected  while  the  attention  of  the  engineer  was  centered  on 
the  steam  engine,  still  the  former  had  been  built  and  actually 
used  long  before  Watts  constructed  his  atmospheric  steam  engine. 
Because  of  defects  of  operation  in  the  internal  combustion 
engine  that  seemed  impossible  of  solution,  the  steam  engine 
took  precedence,  and  it  was  only  during  the  latter  part  of  the 
nineteenth  century  that  the  gas  engine  began  to  come  into 
commercial  favor. 

Huyghens. — While  several  scientists  had  suggested  the  use 
of  gunpowder  in  a  closed  vessel  as  a  source  of  power,  Huyghens 
appears  to  have  been  the  first  who  actually  built  an  internal 
combustion  engine  (1680).  His  design  embodied  an  open- 
ended  cylinder  with  a  piston.  The  powder  was  exploded  when 
the  piston  was  at  the  bottom  of  the  cylinder:  the  explosion 
forced  the  piston  upward.  The  gases  were  expelled  through 
leather  valves,  and  the  cooling  of  the  gases  that  remained  in  the 
cylinder  created  a  vacuum.  The  atmospheric  pressure,  acting 
on  the  piston,  forced  it  downward  into  the  cylinder,  doing  work 
by  its  movement.  Many  structural  defects  caused  the  abandon- 
ment of  this  design. 

Barber's  Producer  Gas  Engine. — The  internal  combustion 
engine  was  practically  ignored  until  1791  when  an  Englishman, 
John  Barber,  built  an  engine  which  made  use  of  gas  distilled 
from  coal.  The  essential  features  of  Barber's  engine  were  the 
use  of  a  mixing  chamber  wherein  the  air  and  producer  gas  were 
mixed  and  ignited,  and  the  employment  of  a  paddle-wheel  against 
the  blades  of  which  the  gases,  issuing  from  the  chamber,  im- 
pinged. This  machine  was  in  reality  a  gas  turbine  rather  than 
a  gas  engine,  and  several  modern  engineers  have  worked  on  the 

1 


2' 


OIL  ENGINES 


design  of  a  gas  turbine  along  the  same  lines.  Barber  patented 
this  engine  in  1791. 

Lenoir. — Although  a  number  of  experimenters  interested 
themselves  in  the  problem  of  building  an  internal  combustion 
engine,  Lenoir  was  the  first  to  manufacture  a  marketable  engine 
in  1860. 

The  Lenoir  engine,  Fig.  1,  was  double  acting;  the  valves  were 
of  the  flat-ported  type,  somewhat  along  steam  engine  practice, 
being  operated  by  eccentrics.  The  gas  and  air  were  mixed  in 
the  inlet  valve  and  passed  into  the  cylinder  under  the  suction 
effect  of  the  retreating  piston.  When  the  piston  was  almost 


GASANOAIR 
SIDE 


FIG.   1. — Lenoir's  gas  engine. 

halfway  in  its  stroke,  the  charge  was  ignited.  The  pressure 
then  rose  to  the  vicinity  of  75  pounds.  The  piston  continued  to 
the  end  of  its  stroke,  being  acted  upon  by  the  gas  pressure.  The 
exhaust  valve  then  opened,  and  the  burnt  products  were  pushed 
out  by  the  piston  on  the  return  stroke.  Hundreds  of  these 
engines  were  placed  in  commercial  use,  but  the  gas  consumption 
was  high,  the  efficiency  being  but  little  above  4  per  cent. 

Otto's  Engine. — About  this  time,  1866,  Otto,  in  Germany, 
designed  an  engine  with  a  free  piston.  In  this  engine,  which  was 
builjt  vertically  with  the  cylinder  below  the  crankshaft,  the  piston 
waft  forced  upward  by  the  explosion.  The  weight  of  the  piston 
then  caused  it  to  descend  into  the  cylinder,  assisted  by  the 
.acuum  formed  by  the  cooling  of  the  gases.  In  descending, 
the  piston  engaged  a  rack  which  turned  the  crankshaft  through 
a  clutch.  The  inertia  of  the  flywheel  started  the  piston  on  the 


HISTORICAL  3 

upward  stroke,  and  the  vacuum  formed  drew  in  a  gas  charge. 
This  charge  was  exploded  when  the  piston  was  partly  advanced 
on  the  upstroke.  It  is  apparent  that  this  embodied  the  same 
principles  as  did  Lenoir's  engine. 

Beau  de  Rochas. — In  1862  Beau  de  Rochas,  a  Frenchman, 
proposed  the  cycle  that  is  at  present  used  by  the  majority  of 
gas  engines.  His  proposal,  although  he  never  actually  built 
an  engine,  was  as  follows : 

The  essential  factors  in  obtaining  high  efficiency  are:  first, 
the  highest  possible  compression  pressure  at  the  moment  of 
ignition;  second,  the  greatest  possible  expansion  of  the  gases 
after  combustion. 

To  achieve  the  desired  efficiency  in  an  engine,  de  Rochas 
proposed  that  an  engine  should  operate  on  the  four-stroke- 
cycle  principle,  having  the  following  events: 

Stroke  1.  Draw  in  the  air  and  gas  charge. 

Stroke  2.  Compression  of  the  charge. 

Stroke  3.  Ignition  and  expansion  of  the  charge. 

Stroke  4.  Discharge  of  the  burnt  gases. 

It  is  to  be  observed  that  these  events  are  those  occurring  in 
all  present-day  four-stroke-cycle  gas  or  gasolene  engines. 

Otto's  Silent  Engine. — As  stated  heretofore,  Otto  had  obtained 
a  patent  on  a  free  piston  engine  in  1866.  In  company  with 
Langen,  Otto  formed  an  engine-building  organization — the 
Gas-Motorem  Fabrik  Deutz — which  is  still  in  existence.  Objec- 
tionable features  of  the  Otto  and  Langen  engine  caused  them  to 
adopt  the  design  proposed  by  Beau  de  Rochas.  This  engine, 
which  was  known  as  the  "Otto  Silent,"  created  a  furor  at  the 
Paris  Exhibition  in  1878.  Figure  2  shows  a  view  of  one  of  these 
early  Otto  engines,  while  Fig.  3  is  a  section  through  the  intake 
valve.  This  valve  has  two  passages  in  it.  The  port  M  is  the 
air  passage,  which,  on  the  suction  stroke  of  the  engine,  is  in  line 
with  m,  the  air-suction  pipe;  Q  is,  at  this  time,  in  contact  with  a; 
and  n  communicates  with  L,  the  gas  passage.  This  allows  the 
air  and  gas  to  enter  the  cylinder  through  a.  As  the  valve  con- 
tinues to  move  to  the  left  on  the  compression  stroke  of  the  piston, 
N  receives  a  small  charge  of  gas  from  the  gas  line  d.  As  the  vt 
moves  to  the  right  on  its  return  stroke,  the  cavity  N  moves  pa 
B,  which  carries  an  open  flame,  and  the  gas  in  N  ignites.  When 
this  passage  moves  past  the  passage  a,  the  flame  in  N  ignites  the 
gas  in  the  cylinder.  The  exhaust  valve,  not  shown,  was  of  the 


4  OIL  ENGINES 

wt  type.  The  disadvantage  lay  in  the  flat  admission  valve. 
To  keep  it  against  its  seat,  a  strong  spring  pressure  was  nec- 
essary; this  occasioned  rapid  wear.  However,  the  engine  was 
.Superior  to  its  competitors  that  thousands  were  sold  all  over 


Fro.   2. — Otto's  silent  engine. 


FIG.  3. — Cross-section  of  Otto's  silent  engine  valve. 

Europe.  It  is  to  be  noticed  that  the  cycle  used  should  have  been 
termed  the  "Beau  de  Rochas  cycle"  instead  of  the  Otto,  by  which 
latter  name  this  cycle  is  now  universally  designated. 

This  engine,  modified  to  better  meet  existing  conditions,  is 
in  daily  use  all  over  the  world;  thousands  are  sold  each  year; 
one  American  firm  in  1917  marketed  30,OOO^Otto  cycle  engines 
in  sizes  from  1 J^  to  10  h.p.,  and  there  are  scores  of  manufacturers 
who  produce  from  1000  to  10,000  engines  yearly. 


HISTORICAL  5 

Bray  ton's  Constant  Pressure  Engine. — A  few  years  previous 
to  the  design  of  the  Otto  silent  engine,  Geo.  Brayton,  a  Phila- 
delphian,  secured  patents  on  an  engine  that  differed  from  all 
other  internal  combustion  engines  in  that,  instead  of  the  charge 
burning  at  constant  volume  or  instantaneously  as  in  the  Otto 
cycle,  the  fuel,  either  gas  or  liquid,  was  introduced  into  the 
cylinder  in  such  a  manner  as  to  cause  it  to  burn  at  constant  pres- 
sure. The  design  of  this  engine  embodied  the  use  of  an  engine 
cylinder  and  of  a  separate  charging  or  compressing  cylinder. 
The  gas  and  air  were  introduced  into  this  charging  cylinder  and 
compressed.  At  the  beginning  of  the  power  stroke  in  the  engine 
cylinder  the  mixture  passed  into  the  cylinder  through  the  intake 
device,  which  was  in  the  form  of  a  gauze  screen.  A  pilot  light 
ignited  the  charge  as  it  blew  into  the  cylinder  until  cut-off  took 
place  at  about  10  per  cent,  of  the  engine  stroke.  The  flow  of 
the  mixture  was  such  that  the  pressure  in  the  power  cylinder  did 
not  increase  during  combustion.  After  the  flow  of  fuel  ceased, 
the  burnt  gases  expanded  as  in  any  engine.  This  Brayton  cycle 
had  much  to  commend  it.  It  was  the  most  efficient  of  all  cycles 
operating  between  the  same  temperature  limits.  Its  drawback 
was  that,  for  equal  power,  it  required  a  much  larger  cylinder  vol- 
ume than  did  the  Otto  cycle.  The  serious  objection,  both  from 
a  manufacturing  and  operating  standpoint,  was  the  excessive 
size  and  weight  of  the  engine  as  well  as  the  complicated 
mechanims.  This  cycle  was  early  abandoned  in  favor  of  the 
more  simple  Otto  cycle. 

Clerk's  Two-cycle  Engine. — This  engine  was  the  design  of 
Dugan  Clerk,  and,  in  place  of  being  four-stroke-cycle,  the 
engine  was  of  the  two-stroke-cycle  type.  The  design  em- 
bodied the  use  of  a  charging  cylinder  into  which  the  air  and  gas 
was  introduced  and  compressed.  The  engine  cylinder  used 
no  exhaust  valves  but,  instead,  made  use  of  ports  about  the 
cylinder.  After  the  power  stroke  was  almost  completed,  the 
piston  uncovered  these  ports,  allowing  the  exhaust  gases  to 
blow  out.  At  the  same  time  the  changing  cylinder  forced  a 
charge  of  air  and  gas  into  the  engine  cylinder.  This  charge 
assisted  in  freeing  the  cylinder  of  the  remaining  consumed  gases 
and  was  compressed  by  the  piston  on  its  return  stroke.  At  the 
proper  time  a  gas  flame,  and  in  some  engines  a  hot  bolt  on  the 
piston,  ignited  the  charge.  This  cycle  was  not  so  favorably 
received  since  it  was  not  as  simple  as  the  Otto  engine.  Sub- 


6  OIL  ENGINES 

sequently,  many  engines  were  built  using  this  two-cycle  principle 
but  compressing  the  gas  and  air  in  the  crankcase  in  preference 
to  the  separate  charging  cylinder.  The  Clerk  engine  was  the 
forerunner  of  the  modern  two-cycle  engine. 

Hornsby-Ackroyd  Engine. — This  engine,  which  was  the 
pioneer  of  all  the  Hot-Bulb  or  "  Surface  Ignition""  engines,  was 
an  English  product.  It  is  still  being  manufactured  in  England 
and  in  the  United  States,  though  the  design  has  been  consider- 
ably improved. 

This  engine  was  of  the  four-stroke-cycle  principle,  the  valves 
being  placed  in  a  valve  chamber  at  one  side  of  the  cylinder. 
The  cylinder  head  included  a  vaporizer  or  uncooled  bulb. 
The  oil  was  injected  into  the  bulb  and,  ,  owing  to  the 
intense  heat  contained  in  the  walls  of  the  bulb,  was  vaporized. 
At  the  end  of  the  compression  stroke  the  heat  of  the  bulb, 
increased  by  the  heat  caused  by  the  compression  in  the  cylinder, 
was  high  enough  to  ignite  the  fuel.  The  engine  was  an  explo- 
sive or  constant-volume  engine  and  followed  the  Otto  cycle  in 
its  action. 

Since  the  engine  used  the  four-stroke-cycle,  the  air  charge  was 
compressed  in  the  engine  cylinder.  The  compression  pressure 
seldom  exceeded  60  Ibs.  per  sq.  inch.  While  this  was  as  high  a 
pressure  as  the  first  engine  could  use  due  to  preignition  troubles, 
later  modifications  of  this  engine  have  the  compression  as  high 
as  140  Ibs.  per  sq.  inch.  The  variation  in  compression  depends 
on  the  time  of  depositing  the  fuel  charge  in  the  vaporizer.  In 
the  early  models  the  oil  entered  the  cylinder  very  early  in  the 
compression  stroke,  while  the  later  designs  have  the  oil  injection 
occurring  during  the  last  45  degrees  before  dead-center. 

The  hot-bulb  or  vaporizer  engine  came  into  general  favor 
based  on  its  ability  to  successfully  burn  kerosene  (termed 
paraffine  in  England)  and  on  the  simplicity  of  design,  which 
made  it  far  superior  to  the  ordinary  four-stroke-cycle  gasolene 
or  carburetor  engine. 

The  trend  during  the  past  fifteen  years  is  toward  a  two- 
stroke-cycle  engine  using  the  crankcase  or  front  of  the  cylinder 
as  a  scavenging  air  compressor.  This  present-day  engine  is, 
in  respect  to  the  method  of  fuel  ignition  and  combustion,  the 
original  Hornsby-Ackroyd;  the  chief  departure  from  this  orig- 
inal design  is  the  change  from  four-stroke-cycle  to  two-stroke- 
cycle.  This  change  lowers  the  manufacturing  costs  and  in 


HISTORICAL  7 

some  respects  simplifies  the  operating  details.  In  the  number 
of  builders  and  in  the  total  horsepower  capacity  of  these  two- 
cycle  hot-bulb  engines  the  United  States  easily  ranks  first. 
In  England  and  on  the  Continent  more  attention  was  given  the 
vaporizer  engine,  and  it  was  as  late  as  1910  before  the  hot-bulb 
came  into  favor  in  England.  At  the  present  time  they  are 
finding  a  field  of  usefulness  in  stationary  work  and  in  small 
vessels,  such  as  fishing  boats,  tugs  and  cruising  yachts. 

The  Diesel  Engine. — The  practice  has  always  been  for  the 
inventor  or  engine  builder  to  construct  his  engine  and  then 
from  its  operation  deduce  the  thermodynamic  principles  under 
which  it  operated.  Dr.  Diesel,  a  German  engineer,  designed 
an  engine  to  operate  on  the  constant  temperature  cycle.  In 
this  engine  the  air  charge  on  the  compression  stroke  was  to 
be  compressed  to  a  pressure  such  that  the  resulting  temperature 
was  above  the  ignition  temperature  of  the  fuel.  The  fuel  was 
to  be  introduced  into  the  cylinder  at  a  rate  such  as  to  cause  the 
heat  released  by  the  combustion  to  exactly  equal  the  work  per- 
formed on  the  moving  piston.  This  would  cause  the  cylinder 
temperature  to  remain  constant  during  the  period  of  fuel  intro- 
duction extending  over  some  10  per  cent,  of  the  piston  stroke. 
After  "cuttoff"  the  gases  were  to  expand  adiabatically  without 
absorbing  or  losing  any  heat  save  that  consumed  in  doing  work; 
the  exhaust  was  to  be  at  constant  pressure.  The  engine  was 
originally  designed  without  water-jacket  cooling  since  there 
was  to  be  no  heat  loss. 

The  original  patent,  dated  1892,  outlined  an  engine  wherein 
the  fuel  used  was  to  be  pulverized  coal  or  coal  dust.  This  coal 
was  to  be  stored  in  a  hopper  immediately  above  the  engine- 
cylinder  head.  Between  the  hopper  and  the  cylinder  was  inter- 
posed a  rotary  valve  having  a  cavity  or  pocket.  The  valve 
received  a  charge  of  coal  dust  and  in  rotating  in  its  seat  came  in 
communication  with  the  cylinder.  The  coal  dust  then  dropped 
into  the  combustion  space  as  the  piston  reached  the  end  of  the 
compression  stroke.  The  fuel  charge  was  varied  to  suit  load 
conditions  through  the  governor  control  of  the  valve  movement. 

Another  interesting  feature  was  the  proposed  introduction 
of  a  water  charge  at  the  beginning  of  the  compression  stroke 
for  the  purpose  of  keeping  the  compression  pressure  under 
control. 

A  second  claim  embodied  in  the  same  patent  covered  the  use 


8  OIL  ENGINES 

of  liquid  fuels  with  the  employment  of  a  spraying  valve  but 
without  the  air  injection  feature.  The  engine  was  to  be  started 
by  some  explosive  agent  in  the  cylinder  for  the  initial  stroke. 
The  expansion  was  to  be  carried  to  such  a  point  that  the  exhaust 
gases  were  to  be  cold  enough  to  be  used  as  the  cooling  medium 
in  the  cylinder  jacket. 

An  engine  was  constructed  along  these  lines  but  never  turned 
over  beyond  the  initial  stroke,  during  which  it  was  completely 
wrecked.  At  this  late  date  no  information  seems  available  as 
to  the  cause  of  this  wreck,  but  it  is  to  be  presumed  that  the 
starting  charge  of  explosives  was  the  destructive  agent. 

This  disappointment  caused  the  builders  of  this  engine  to 
partially  abandon  Dr.  Diesel's  ideas,  and  a  water-cooled  engine 
was  built  in  which  the  admission  of  heat  was  at  constant  pres- 
sure instead  of  at  constant  temperature  as  originally  contem- 
plated by  Dr.  Diesel.  The  first  of  these  later  engines  actually 
ran  but  never  was  able  to  carry  any  load.  The  development 
of  the  Diesel  proceeded  slowly  for  a  few  years,  and  it  was  not 
until  1897-1898  that  a  commercial  engine  was  produced,  this 
being  a  single-cylinder  25  h.p.  engine  of  vertical  design  and  using 
a  crosshead. 

From  this  modest-powered  engine  it  was  but  a  question  of  a 
relatively  few  years  before  engines  of  a  thousand  horsepower 
per  cylinder  were  in  commercial  use.  The  engine  was  patented 
in  practically  every  country,  and  for  a  few  years  all  European 
manufacturers  operated  under  a  license;  this,  however,  was 
discontinued  around  1904,  and  but  few  manufacturers  paid 
royalties.  The  popularity  of  the  Diesel  engine  in  Europe  has 
been  due,  to  a  large  extent,  to  the  type  of  manufacturer 
building  these  engines.  In  Germany  a  number  of  the  strongest 
steam  engine  builders,  having  the  facilities  to  do  the  extensive 
experimenting  necessary,  early  took  up  this  engine.  In  Switzer- 
land and  the  Scandinavian  countries  the  engine  found  early 
favor.  The  British  Diesel  Engine  Co.,  even  when  the  engine 
temporarily  fell  into  disrepute  in  Germany,  continued  their 
labors,  and  much  credit  for  the  successful  outcome  of  the  Diesel, 
usually  attributed  to  German  firms,  actually  is  due  to  the  ac- 
tivities of  the  British  manufacturers. 

The  Diesel  was  introduced  into  the  United  States  by  Adolphus 
Busch  of  St.  Louis.  The  first  American  Diesel  engine  was  com- 
pleted in  1898,  being  of  the  two-cylinder  vertical  A-frame  design, 


HISTORICAL  9 

and  developed  60  h.p.  The  early  history  of  the  Diesel  engine 
in  America  was  one  of  disappointment;  part  of  the  adverse 
criticism  of  the  engine  that  is  encountered  even  now  is  the  result 
of  the  policies  of  the  early  firms.  During  the  past  five  years  a 
number  of  American  engine  builders  have  taken  up  the  manufac- 
ture of  the  engine;  the  designs,  in  the  main,  follow  European 
practice,  though  in  the  tendency  toward  horizontal  frames  can  be 
detected  the  objection  which  the  American  engineer  has  toward 
the  vertical  type  engine. 

Diesel  Marine  Engine. — It  is  for  marine  work  that  the  Diesel 
possesses  many  favorable  characteristics,  and  the  past  two  years 
have  found  the  majority  of  builders  engaging  their  shop  facilities 
in  the  manufacture  of  this  type  of  Diesel.  The  first  marine 
Diesel  was  constructed  in  1903  by  French  engineers  for  use  on  a 
canal  boat.  This  particular  engine  was  single  cylindered  with 
opposed  pistons  and  worked  on  the  four-stroke-cycle.  While 
French  firms  produced  a  considerable  horsepower  of  the  marine 
engines,  the  greatest  development  occurred  in  Russia  where  the 
demand  for  river  boat  engines  stimulated  the  activities  of  the 
Diesel  builders.  Credit  must  also  be  given  to  Nobel  Bros,  of 
Petrograd  for  the  production  of  the  first  Diesel  for  submarine 
service  in  1908.  This  phase  of  Diesel  manufacture  has  received 
great  attention  since  1914,  and  undoubtedly  the  greatest  improve- 
ments in  design  have  occurred  on  the  submarine  engine. 

While  of  late  years  engines  have  been  built  having  a  capacity  of 
2000  h.p.  per  cylinder,  the  American  operator  is  actually 
concerned  in  engines  ranging  below  1200  h.p.  per  unit. 


CHAPTER  II 


THE  DIESEL  ENGINE 

Cycle  of  Events. — The  readers  who  are  familiar  with  the  opera- 
tion of  a  gasolene  engine  should  easily  grasp  the  cycle  of  events 
occurring  in  the  cylinder  of  the  Diesel  engine.  In  Fig.  4,  a  to  d, 
are  shown  four  conditions  existing  in  the  engine  cylinder  at 


2d  Compression 
Stroke 


FIG.  4. — Working    diagram    of    four-stroke-cycle    Diesel    engine. 

various  points  of  the  piston's  stroke,  while  Fig.  4e  indicates  the 
portion  of  the  stroke  as  covered  by  each  event. 

In  Fig.  4,  drawing  a  covers  the  suction  or  admission  stroke 
of  the  piston.     The  admission  valve  J  has  opened  at  the  point  A 

10 


THE  DIESEL  ENGINE  11 

just  before  dead-center.  The  valve  J  remains  open  from  the 
point  A  to  the  point  B.  This  admission  stroke  is  shown  in  Fig. 
4e  and  Fig.  4/;  in  the  latter  the  indicator  card  shows  this  line 
as  being  below  the  atmospheric  pressure  line  xy.  The  air  ac- 
tually enters  the  cylinder  under  suction  pressure.  In  drawing  b, 
Fig.  4,  the  admission  valve  J  has  closed  at  B,  and  the  pure  air 
charge  is  compressed  by  the  piston  up  to  the  point  G,  which  is 
top  dead-center.  This  process  is  covered  by  the  compression 
line  BC  on  the  indicator  card  in  Fig.  4/.  The  clearance  volume 
is  very  small,  and  the  maximum  or  final  compression  pressure 
rises  to  some  500  to  550  Ibs.  per  sq.  inch.  The  work  done  on 
the  air  charge  in  compression  causes  the  temperature  to  ascend 
to  about  1100°  Fahrenheit. 

At  the  point  C  in  drawing  c,  Fig.  4,  the  injection  valve  opens, 
and  a  charge  of  fuel  is  blown  into  the  cylinder  by  means  of  a  blast 
of  high-pressure  air.  The  injection  valve  is  designed  to  cause  the 
rate  of  flow  through  the  valve  to  be  " braked"  so  that  the  in- 
jection is  not  instantaneous  but  takes  place  while  the  engine  crank 
turns  through  a  considerable  angle.  In  drawing  c,  Fig.  4,  the 
injection  of  fuel  starts  when  the  crank  is  at  C  and  ends  when  the 
crank  is  at  D.  In  Fig.  4/  the  line  CD  represents  the  admission 
period,  and  the  desired  condition  is  attained  when  the  line  CD  is 
practically  horizontal,  showing  that  the  rate  of  heat  addition  is 
such  that  there  is  no  increase  in  the  cylinder  pressure. 

The  injection  and  the  combustion  of  the  fuel  ceasing  at  the 
point  D,  the  piston  continues  to  the  end  of  its  stroke  under  the 
influence  of  the  expanding  gases.  Before  the  completion  of  the 
stroke,  the  exhaust  valve  L  opens  when  the  crank  is  at  E.  This 
allows  the  gases  to  rush  out  through  the  exhaust  passage.  The 
exhaust  valve  continues  to  remain  open  until  the  piston  again 
ascends  to  the  top  of  the  cylinder,  expelling  all  the  exhaust  gases. 
This  part  of  the  cycle  is  shown  in  drawings  d  and  e  as  continuing 
from  E  to  F]  in  Fig.  4/  this  forms  the  exhaust  line  EF.  Before 
the  exhaust  valve  L  closes,  the  admission  valve  opens  at  A,  allow- 
ing a  fresh  air  charge  to  be  inducted  into  the  cylinder  during  the 
stroke  shown  in  drawing  a. 

These  events  complete  the  cycle  of  the  four-stroke-cycle  Diesel. 
From  a  practical  viewpoint  the  differences  between  the  Diesel 
and  the  gas  engine  are  that  in  the  Diesel  nothing  but  pure  air 
is  compressed  in  the  cylinder  and  that  the  fuel  is  forced  into  the 
cylinder  slowly,  causing  the  combustion  to  be  gradual;  in  the 


12 


OIL  ENGINES 


gas  engine  both  the  gaseous  fuel  and  the  air  are  compressed,  and 
the  combustion  takes  the  form  of  an  explosion. 

Schematic  Layout  of  the  Diesel  Engine. — Figure  5  embodies 
the  schematic  arrangement  of  the  essential  mechanism  of  a 
Diesel  engine.  In  this  particular  instance  the  engine  is  of  the 
horizontal  type  operating  on  the  four-stroke-cycle  principle. 
The  engine  crank  is  represented  with  its  center  at  0,  and  the 
crank  revolves  clockwise.  To  the  crankshaft  is  geared  a  lay- 
shaft  A  which  revolves  at  half-engine  speed.  On  this  layshaft 


FIG.  5. — Schematic    arrangement   of    Diesel    engine    mechanism. 

are  mounted  the  cams  used  to  actuate  the  exhaust,  admission  and 
fuel  injection  valves,  which  are  operated  in  the  sequence  out- 
lined in  Fig.  4.  The  fuel  pump  P  is  driven  off  the  layshaft, 
the  fuel  charge  being  under  control  of  the  governor  Q.  The  fuel 
is  deposited  in  the  injection  valve  C,  out  of  which  it  is  forced  by 
the  air  charge  at  the  proper  moment.  The  air  blast  is  supplied 
by  the  air  compressor  Z),  which  is  driven  by  a  crank  on  the  end 
of  the  engine  shaft.  In  this  diagram  the  air  line  is  not  supplied 
with  a  receiver  or  air  bottle,  and  the  air  is  delivered  directly  from 
the  compressor  to  the  fuel  valve. 

The  parts  enumerated  above  are  the  essential  parts  of  the 
Diesel  engine.  However  the  arrangements  may  differ,  it  is 
necessary  that  the  unit  include  an  air  compressor,  fuel  pump, 


THE  DIESEL  ENGINE 


13 


governor,  camshaft  and  injection  or  fuel  valve  in  addition  to 
those  parts  generally  found  on  an  internal  combustion  engine. 

Figure  6  represents  the  working  diagram  of  a  two-stroke-cycle. 
In  Fig.  66  the  air  charge  is  compressed;  in  Fig.  6c  the  fuel  is 
injected  and  the  piston  forced  downward  on  the  working  stroke; 
in  d  the  piston  uncovers  passages  or  ports  in  the  side  of  the 
cylinder  through  which  the  exhaust  gases  pass.  As  the  piston 
moves  downward  to  the  point  A,  a  valve  in  the  cylinder  head 
opens,  and  a  charge  of  pure  air  which  has  been  compressed  to 


abed 

Scavenging      Cou>pr^ion  Fuel      Exhaust 
Admission 


FIG.   6. — Working  diagram  of  two-stroke-cycle  Diesel  engine. 

about  10  Ibs.  blows  into  the  icylinder,  clearing  it  of  all  exhaust 
gases.  At  B,  or  before  this  point,  the  scavenging  valve  closes, 
and,  as  the  piston  moves  upward,  it  seals  the  exhaust  ports  at  the 
point  B.  Continued  upward  motion  compresses  the  air  charge 
until  upper  dead^-center  is  reached  whereupon  the  cycle  is 
repeated. 

American  Diesel  Engine  Company. — This  company  was  the 
pioneer  Diesel  engine  company  in  the  United  States.  At  the 
present  time  there  are  many  installations  of  the  American 
Diesels  which  have  been  in  operation  for  ten  to  fifteen  years, 
though  they  have  largely  been  replaced  by  units  of  modern 
design.  For  this  reason  the  engine  is  mainly  of  historical 
interest  although  there  is  more  demand  for  experts  to  adjust 
and  repair  these  engines  than  any  other.  This,  of  course,  is 
because  the  engines  have  been  in  service  for  such  lengths  of  time 
that  extensive  overhauls  and  rebuildings  are  necessary. 


14 


OIL  ENGINES 


Figure  7  is  the  cross-section  of  the  American  engine.  Even 
to  the  inexperienced  it  is  evident  that  the  builders  largely  followed 
accepted  gas  engine  designs  in  the  general  construction  of  this 


CjUHia:  Toi  Plate 


Coolin? 
Water 
By-Pass 


Side  Door 
Bandies 


FIG.  7. — Cross  section  of  American   Diesel  engine. 

unit.  The  frame  was  of  the  box  type  and  was  reinforced  by 
tension  rods  to  absorb  the  working  stress.  The  cylinders,  of 
which  there  were  three  per  engine,  were  cast  integral  with  the 


THE  DIESEL  ENGINE  15 

jacket  walls.  The  valves  were  located  at  the  side  of  the  cylinders 
quite  like  the  gas  engine  practice  of  ten  years  ago.  The  box 
frame  was  entirely  enclosed,  though  provided  with  side  doors, 
and  splash  lubrication  was  used.  The  camshaft  was  carried 
inside  of  the  frame  in  bushed  bearings  bolted  to  the  interior 
of  the  frame;  the  gear  reduction  was  2  to  1,  with  an  idler  pinion 
between  the  camshaft  and  the  crankshaft  gears.  The  various 
parts  will  be  discussed  in  succeeding  chapters  as  will  also  the 
parts  of  other  engines. 

The  engine,  when  first  introduced,  was  of  a  type  unknown  to 
the  American  engineer  and,  like  all  new  machines,  suffered  at  the 
hands  of  ignorant  and  unskilled  laborers.  Probably  no  prime 
mover  ever  experienced  the  manhandling  accorded  this  oil  engine. 
Scores  of  cylinder-head  stud  bolts  were  twisted  off  under  the 
efforts  of  a  brawny  laborer  using  a  5-foot  pipe  wrench.  As 
faulty  as  the  engine  was,  it  is  highly  probable  that  it  would  have 
been  fairly  successful  under  the  attention  of  more  skilled 
operators.  It,  however,  served  the  useful  purpose  of  giving 
many  Diesel  engineers  experience.  Later-day  manufacturers 
should,  for  this  reason,  have  a  grateful  feeling  toward  this  pioneer. 

Busch-Sulzer  Bros.  Diesel  Engine. — This  company  represents 
a  reorganization  of  the  American  Diesel  Engine  Co.  In  the 
design  of  the  Type  B  stationary  engine  the  experience  of  their 
Swiss  associates,  Sulzer  Bros.,  has  been  drawn  upon.  The 
engine,  a  view  of  which  appears  in  Fig.  8,  has  four  working 
cylinders,  while  the  air  compressor  is  mounted  on  the  engine  frame 
and  has  much  the  appearance  of  a  fifth  cylinder.  The  frame 
is  of  two-piece  construction,  the  base  carrying  the  shaft  bearings. 
The  upper  portion  of  the  frame  rests  on  the  base  and  is  tied  to 
it  both  by  base  stud-bolts  and  tension  bolts  or  tie  rods. 

The  camshaft  is  mounted  close  to  the  top  of  the  cylinder  and 
is  driven  by  a  vertical  drive  shaft,  which  also  carries  the  governor. 
This  is  shown  in  Fig.  8.  The  camshaft  is  entirely  enclosed,  the 
cams  working  in  an  oil  bath.  Doors  provide  access  to  the 
various  parts.  The  valve  mechanism  has  incorporated  with  it 
a  servomotor,  which  controls  the  injection  point  and  the  air- 
injection  pressure.  The  cam  housing  also  includes  the  support 
for  the  fuel  pumps  which  are  driven  from  off  the  vertical  cam 
drive  shaft. 

Mclntosh  &  Seymour  Diesel  Engine. — This  engine,  of  the  A- 
frame  design,  is  practically  identical  with  the  product  of  the 


16 


OIL  ENGINES 


Aktiebolaget  Diesels  Motorer  (Swedish  Diesel  Engine  Co.) 
of  Sweden.  As  outlined  in  Fig.  9,  the  engine  frame  or  base 
is  a  low  box  section  casting  some  12  inches  in  height.  This 
frame  rests  directly  on  the  foundation.  To  the  base  are  bolted 


the  A-frame  castings,  which  are  of  cylindrical  form  at  the  top 
to  receive  the  cylinder  liner,  in  this  way  acting  as  the  cooling 
jacket  outer  walls.  In  the  500  h.p.  unit  there  are  four 
cylinders  and  A-frames,  while  the  air  compressor  is  mounted  in 


THE  DIESEL  ENGINE 


17 


FIG.  9.— Mclntosh   and   Seymour  Diesels,  Texas  Light  and  Power  Co.,  Paris, 

Texas. 


FIG.   10. — Mclntosh  and  Seymour  box  frame  Diesel. 


18  OIL  ENGINES 

line  with  the  power  cylinders  on  a  similar  A-frame  but  of 
much  lower  height. 

The  camshaft  is  carried  at  a  level  with  the  cylinder  heads  and 
is  driven  by  a  vertical  shaft  and  bevel  gears ;  the  shaft  carries  the 
governor  while  the  fuel  pump  is  supported  on  one  of  the  cylinder 
castings. 

The  Mclntosh  &  Seymour  Corporation  has  now  virtually 
abandoned  the  A-frame  engine  for  stationary  work  and  are 
centering  their  manufacturing  facilities  on  the  box-frame  engine. 
Beyond  the  frame  itself,  the  engine  has  been  modified  in  no 
way,  the  details  of  valves,  governors,  etc.,  remaining  as  before. 
Figure  10  is  a  view  of  the  box-frame  engine.  These  engines 
range  in  size  up  to  1000  B.h.p.,  which  unit  is  of  six-cylinder 
construction. 


FIG.   11. — Snow  four-stroke-cycle  Diesel. 

Worthington  Pump  and  Machinery  Co.  Diesel  Engine. — 
This  corporation  manufactures,  at  the  Snow  Works,  a  Diesel- 
type  engine  under  the  name  of  "The  Snow  Oil  Engine."  This 
engine,  which  is  of  horizontal  construction,  is  manufactured  in 
units  from  65  h.p.  to  800  h.p.  It  does  not  follow 
standard  American  Diesel  engine  practice  in  that  a  cross- 
head  is  used  in  preference  to  a  trunk  piston.  This  necessitates 
the  lengthening  of  the  frame. 

The  main  frame,  Fig.  11,  is  of  box  section  with  both  longitu- 
dinal and  transverse  ribbing.  The  single  and  twin  cylinder  units 
have  a  one-piece  frame,  while  the  frame  of  the  three-cylinder 


THE  DIESEL  ENGINE 


19 


engine,  is  of  two-part  construction  to  facilitate  shipping  and  erec- 
tion. As  seen  by  Fig.  11,  the  frame  is  extended  to  form  the 
cylinder  cooling  jacket;  the  liner  is  separate  and  is  forced  into 
the  jacket  cavity.  The  air  charge  for  the  engine  cylinder  enters 
the  frame  at  one  side  of  the  crankcase  and  flows  along  the  frame 
before  passing  through  the  admission  valve.  The  air  com- 
pressor is  mounted  on  the  engine  frame  and  is  driven  by  a  crank 
keyed  to  the  engine  shaft.  The  valves  are  controlled  by  a  cam- 
shaft placed  transversely  in  front  of  the  cylinder  head ;  this  shaft 
is  driven  through  bevel  gears  by  a  layshaft  at  one  side  of  the 
engine.  This  latter  shaft  also  drives  the  governor  and  fuel 
pumps. 


FIG.   12. — Allis-Chalme'rs  Diesel,  single  cylinder. 

Allis-Chalmers  Diesel  Engine. — The  frame  is  of  the  box 
type,  Fig.  12,  and  is  so  designed  as  to  allow  the  engine  shaft  to 
rest  deep  in  the  bearings.  This  gives  the  engine  a  low  center  of 
gravity,  making  it  rigid  and  fairly  free. from  vibration  while  in 
operation. 

As  with  all  modern  Diesels  the  frame  forms  the  cylinder 
jacket,  while  the  liner  is  held  in  place  by  a  flange  at  the  head  end. 
The  valve  mechanism  is  driven  off  the  longitudinal  layshaft, 
which  also  handles  the  governor  and  fuel  pump.  The  Allis- 
Chalmers  engines  are  manufactured  in  single,  twin,  triple  and 
quadruple  cylinder  units.  The  single  and  twin  engines  are  both 


20 


OIL  ENGINES 


built  with  a  one-piece  frame.  The  triple-cylinder  unit  consists  of 
a  single  and  a  twin  engine  with  the  flywheel  between  the  two  en- 
ginesj  the  two-piece  shaft  being  flanged  and  bolted  to  the  wheel 
hub.  The  quadruple-cylinder  engine  is  obtained  by  using  two 
twins  with  the  flywheel  between  the  two  frames. 

National  Transit  Pump  and  Machine  Co.  Diesel  Engine.— 
The  engine  manufactured  by  this  company  is  of  horizontal 
design,  as  outlined  in  Fig.  13,  which  brings  out  the  massive  lines, 
particularly  those  of  the  bearing  housing  footings.  The  engine  is 


FIG.   13.— National  Transit  Diesel. 


built  in  one  and  two  cylinder  units.  As  usual  with  the  horizontal 
design,  a  layshaft  is  employed  to  control  the  valve  mechanism, 
as  well  as  to  drive  the  pump  and  governor. 

McEwen  Bros.  Diesel  Engine. — This  company  is  one  of  the 
later  firms  to  embark  upon  Diesel  engine  manufacture.  The 
engine  closely  resembles  other  American  units,  being  of  the  hori- 
zontal design,  Fig.  14;  the  cylinder  liner  is  pressed  into  the  jacket, 
which  is  a  part  of  the  frame.  The  piston  is  of  the  standard  trunk 
design.  The  valves  are  vertical,  and  both  admission  and  exhaust 
valves  are  provided  with  cages.  The  valves  are  controlled  by 
separate  eccentrics  while  the  injection  valve  is  actuated  by  a 
cam.  The  air  compressor,  which  is  two-stage,  is  driven  by  a 
crank  extension  of  the  engine  shaft.  No  air  storage  is  employed, 


THE  DIESEL  ENGINE 


21 


FIG.    14. — McEwen  Bros.  Diesel. 


FIG.    15. — De  La  Vergne  Type  F.  D.  four-stroke-cycle  Diesel. 


22  OIL  ENGINES 

a  small  bottle  being  placed  in  the  air  discharge  line  to  absorb 
the  air  pulsations. 

De  La  Vergne  Machine  Co.  Diesel  Engine. — The  De  La  Vergne 
Machine  Co.  has  been  manufacturing  oil  engines  of  the  low- 
pressure  and  the  semi-Diesel  types  for  a  number  of  years.  In 
1918  they  brought  out  their  Type  FD  engine,  which  operates 
on  the  true  Diesel  cycle.  The  engine,  which  appears  in  Fig.  15,  is 
of  horizontal  design,  and  embodies  the  use  of  a  very  rugged 
frame.  The  camshaft  is  borne  in  bearings  in  front  of  the  cylinder 
head  and  is  driven  by  the  longitudinal  layshaft  through  bevel 
gears.  The  valves  lie  horizontally  and  are  actuated  by  short 
cam  levers.  The  fuel  pump  and  governor,  which  are  driven  by 
the  layshaft,  are  similar  to  those  used  on  the  De  La  Vergne  FH 
engine  and  are  the  result  of  a  number  of  years  of  experience. 

Two -stroke -cycle  Diesel. — The  American  manufacturers, 
with  but  few  exceptions,  have  adopted  the  four-stroke-cycle 
engine.  In  this  they  were  undoubtedly  influenced  by  the  greater 
freedom  from  operating  difficulties  which  this  type  possesses 
over  the  two-stroke-cycle.  To  the  uninitiated  it  would  appear 
that  the  two-stroke-cycle  engine  was  simpler,  due  to  the  elimina- 
tion of  the  admission  and  exhaust  valves.  However,  the  design 
calls  for  the  incorporation  of  some  form  of  scavenging  air  com- 
pressor since  an  air  charge  must  be  used  to  force  the  burnt  gases 
out  the  exhaust  ports  when  the  ports  are  uncovered  by  the  piston. 
If  the  fuel  consumption  is  to  approach  that  of  the  four-stroke- 
cycle,  the  scavenging  air  charge  must  enter  the  cylinder  at  the 
cylinder  head  in  order  that  the  scavenging  be  successful.  If 
air  ports  are  used,  the  eddy  currents  set  up  by  the  air  as  it  enters 
the  cylinder  somewhat  destroy  its  scavenging  effect. 

The  two-stroke-cycle,  chiefly  on  account  of  the  lighter  weight 
per  horsepower,  has  been  in  favor  in  marine  work.  It  has  not 
won  complete  possession  of  this  field,  and  at  present  the  swing  is 
strongly  toward  the  four-cycle.  For  the  small-powered  boat 
under  200  h.p.  rating  and  for  the  large  motorships  calling 
for  engines  of  2000  h.p.  or  greater,  the  two-stroke-cycle 
engine  is  better  adapted  than  is  the  four-stroke-cycle.  This 
applies  especially  to  submarine  boats,  even  though  the  latter 
engine  is  more  popular  in  this  field  at  the  present  time. 

The  Southwark-Harris  Diesel  Engine. — The  Southwark 
Foundry  and  Machine  Co.  is  manufacturing  a  two-stroke-cycle 
engine  that  is  applicable  both  for  stationary  and  marine  work. 


THE  DIESEL  ENGINE 


23 


This  engine,  a  cross-section  of  which  is  shown  in  Fig.  16,  is  of 
vertical  design  and  has  cylinders  ranging  in  number  from  four  to 
eight,  dependent  on  the  horsepower  rating. 


FIG.   16. — Southwark-Harris  two-stroke-cycle  Diesel. 

The  engine  is  provided  with  a  base  or  crankcase,  to  which  is 
bolted  the  vertical  support  for  the  cylinder.  This  cast-iron 
support  is  at  one  side  only,  the  other  side  being  supported  by  ten- 
sion rods.  This  makes  the  engine  frame  very  open  when  the 
steel  guards  are  removed.  The  cylinder  and  water  jacket  are 


24  OIL  ENGINES 

cast  in  one  piece;  this  is  not  objectionable  on  cylinders  12  inches 
in  diameter.  Use  is  made  of  a  stepped  piston,  the  differential  cav- 
ity being  used  for  the  scavenging  air  compressor  and  for  air  starting 
as  well.  Since  this  engine  is  quite  different  from  standard  designs, 
a  brief  description  of  the  method  of  operation  is  included. 

The  starting  air,  at  200  Ibs.  pressure,  which  has  been  stored 
in  an  air  tank,  is  admitted  into  the  differential  cylinder  above  the 
piston  P2-  This  forces  the  piston  downward,  and  the  engine 
turns  over.  The  engine  is  turned  over  twice  with  the  air,  and 
the  fuel-injection  mechanism  is  thrown  into  play.  The  cylinders 
are  connected  in  pairs  through  the  scavenging  manifold  M, 
while  the  cranks  of  the  paired  cylinders  are  set  at  180  degrees. 
With  the  working  piston  of  cylinder  No.  1  at  top-center  a  fuel 
charge  is  injected  through  the  needle  valve  N.  The  piston  is 
forced  downward  on  the  power  stroke  while  the  piston  in  cylinder 
No.  2  is  moving  upward  on  the  compression  stroke.  The  scaveng- 
ing or  stepped  piston  P2  of  No.  2  cylinder  is  at  the  same  time 
compressing  its  charge  of  air  to  a  pressure  of  around  7  pounds 
gage.  When  the  working  piston  PI  in  No.  1  cylinder  has  moved 
over  80  per  cent,  of  its  stroke,  it  uncovers  the  exhaust 
ports  E,  allowing  the  burnt  gases  to  escape.  At  the  same  time 
the  scavenging  air  ports  D  are  uncovered,  and  the  scavenging 
air  from  No.  2  scavenging  cylinder  flows  up  the  passage  A, 
through  the  valve  F2,  and  into  the  manifold  M,  which  connects 
with  the  air  ports  Z>.  This  air  blowing  into  No.  1  working 
cylinder  scavenges  the  cavity  of  the  exhaust  gases  and  fills  the 
cylinder  with  a  pure  air  charge.  The  same  events  occur  in  No.  2 
cylinder  on  the  next  stroke  since  the  scavenging  cylinder  of  No.  1 
has  drawn  in  its  air  charge  through  the  port  G  and  muffler  S 
when  the  downward  movement  of  No.  1  piston  uncovered  the 
port  G. 

The  camshaft  is  mounted  along  one  side  of  the  cylinders  and 
drives  the  fuel  valves  through  bell-cranks  and  push-rods.  As 
pointed  out  above,  two  fuel  valves  are  used.  This  necessitates 
the  use  of  two  fuel  cams  per  cylinder,  the  cam  noses  being  slightly 
less  than  180  degrees  apart  for  each  cylinder.  One  feature  of 
this  engine  that  has  merit  is  the  variable  lift  of  the  fuel  valves. 
The  push-rod  K  rests  on  the  upper  surface  of  the  rocker  or  bell- 
crank  R.  A  movement  of  the  crank  KI  slides  the  push-rod 
roller  along  the  rocker  R,  thereby  producing  a  change  in  the  valve 
lift.  The  engine  then  has  two  fuel  controls — variable  valve  lift 


THE  DIESEL  ENGINE  25 

and  variable  fuel  charges.  The  variation  in  valve  lift  is  under 
manual  control  only,  unlike  those  engines  using  a  servomotor 
which  automatically  secures  the  same  advantages.  This  repre- 
sents the  method  of  operation.  The  action  of  the  fuel  pump  will 
be  discussed  in  the  chapter  devoted  to  fuel-pumping  mechanisms. 
Standard  Fuel  Oil  Engine  Co.  Two-stroke-cycle  Diesel 
Engine. — The  Diesel  engine  manufactured  by  this  firm  is  of 
the  two-cycle  type,  Fig.  16A.  The  piston  is  stepped,  and  the 
scavenging  air  is  compressed  by  the  enlarged  section  of  the  piston. 


FIG.   16A. — Standard  Fuel  Oil  twin  cylinder  two-stroke-cycle  Diesel. 

The  frame  casting  is  massive  in  design.  The  cylinder  casting 
fits  into  the  bored  frame  cavity,  which  design  gives  a  rigid 
support  to  the  working  cylinder.  The  method  of  fuel  injection 
and  air  scavenging  will  be  discussed  in  a  later  chapter. 

Nobel  Bros.  Marine  Diesel. — The  honor  of  building  the  first 
commercial  line  of  marine  Diesels  belongs  to  this  Russian  firm. 
Since  the  demand  was  for  Diesels  to  engine  the  river  and  ferry 
boats,  the  units  Nobel  Bros,  produced  were  all  of  small  powers — 
ranging  from  50  to  200  h.p.  The  same  firm  was  the  first 
to  adopt  the  Diesel  engine  to  submarine  boats.  The  Russian 
government  leaned  to  the  small-dimensioned  sub-boats,  conse- 
quently the  development  of  the  Nobel  Bros,  submarine  Diesel 
has  been  along  the  smaller  units  below  200  h.p.,  although  they 


26  OIL  ENGINES 

produced  a  900  horsepower  submarine  Diesel  prior  to  1914. 
Like  all  new  apparatus  the  Nobel  Diesel  has  undergone  various 
changes  in  design. 

Werkspoor  Marine  Diesel. — The  first  ocean-going  motorship  of 
any  size  equipped  with  a  Diesel  engine  was  the  Vulcanus.     This 


FIG.  17.  —  Cross-section  of  Werks- 
poor  Diesel  on  the  motor-ship 
"Vulcanus." 


FIG.     18.  —  Werkspoor     open     frame 
marine  Diesel. 


boat  was  a  1000-ton  tank  ship  fitted  with  a  450  h.p.  Werkspoor 
engine  having  cylinders  15.7  inches  diameter  by  3  1.5  inches  stroke, 
operating  at  180  r.p.m.  This  engine  is  shown  in  Fig.  17. 
Although  the  design  necessitated  an  increased  height,  the  cross- 


THE  DIESEL  ENGINE 


27 


28 


OIL  ENGINES 


head  type  piston  was  used.  To  eliminate  the  piston-heating 
risk,  water-cooling  through  telescopic  tubes  was  used.  The  frame 
was  of  box  design  and  was  early  abandoned  for  the  present 
Werkspoor  frame  which  consists  of  steel  columns.  This  later 
construction  is  illustrated  in  Fig.  18.  This  engine  is  being 
manufactured  in  the  United  States  by  the  Midwest  Engine  Co., 
the  Pacific  Skandia  Co.  and  the  New  York  Shipbuilding  and 
Engine  Co. 


FIG.  20. — 600  H.P.   Mclntosh  and  Seymour  marine  Diesel  four-stroke-cycle 

reversible  type. 


Nelseco  Marine  Diesel. — The  New  London  Ship  and  Engine 
Co.  manufactures  both  two-  and  four-stroke-cycle  marine  Diesels. 
Figure  19  is  a  cross-section  of  the  latter  type  engine.  This  engine 
is  built  both  reversing  and  non-reversing. 

Mclntosh  &  Seymour  Marine  Diesel. — Figure  20  is  a 
view  of  the  marine  Diesel  manufactured  by  this  firm,  while 
Fig.  21  shows  section  and  end  elevations.  The  engine  is 
reversible  through  the  shifting  of  the  camshaft,  as  will  be  dis- 
cussed in  the  chapter  on  valve  gears. 


THE  DIESEL  ENGINE 


29 


30 


OIL  ENGINES 


zai 


THE  DIESEL  ENGINE 


31 


Fulton  Machine  Works  Marine  Diesel. — This  company  was 
the  pioneer  manufacturer  of  marine  Diesels  of  small  power. 
These  units,  Fig.  22,  range  from  32  to  100  h.p.  in  size  and  are 
equipped  with  a  reversing  clutch. 

Lyons-Atlas  Co. — The  Lyons-Atlas  Co.  brought  out  a  vertical 
Diesel,  Fig.  23,  from  their  own  designs.  There  are  several  of 


FIG.   23. — Lyons-Atlas  Diesel.     Original  Design. 

these  units  in  the  United  States.  The  company  was  reorganized 
as  the  Midwest  Engine  Co.  and  is  now  manufacturing  the 
Werkspoor  Diesel. 

Nordberg  Manufacturing  Co.  Diesel  Engine. — This  company 
manufactures  the  Carels  Diesel  in  both  two-  and  four-stroke- 
cycle  designs. 


CHAPTER  III 

INSTALLATION  OF  AN  OIL  ENGINE 

General. — The  average  engineer  takes  up  the  problem  of 
installing  an  oil  engine  with  a  feeling  of  foreboding  and  dread. 
This  is  due  to  his  inexperience  in  this  character  of  work.  It  is 
not  an  impossible  task;  indeed,  it  can  hardly  be  termed  difficult 
if  the  matter  is  approached  with  composure.  Under  ordinary 
conditions  the  engine  builder  insists  on  supplying  an  erector 
as  a  safeguard  that  his  interests  are  protected.  Certain  details, 
such  as  excavation,  foundation  work,  etc.,  are  delegated  to  the 
purchaser.  Even  in  the  actual  work  of  assembly  many  factory 
engineers  place  the  responsibility  of  setting  the  frame  on  the 
foundation  onto  the  plant  engineer.  If  the  latter  is  capable, 
he  will  speedily  find  that  he  must  direct  the  erection  of  the  entire 
engine  with  the  exception  of  a  few  important  parts.  Since  there 
are  many  second-hand  oil  engines  offered  for  sale,  it  behooves 
the  engineer  to  place  himself  in  possession  of  sufficient  knowledge 
to  enable  him  to  erect  any  of  these  that  might  be  purchased. 

Excavation. — The  first  problem  that  presents  itself  is  the 
matter  of  foundation  excavation.  With  small  belted  units 
the  easiest  and  the  best  procedure  is  to  make  the  foundation  pit 
rectangular,  of  the  size  shown  on  the  manufacturer's  setting 
plan.  Use  can  then  be  made  of  the  earth  sides  of  the  pit  as  the 
form  walls.  If  the  foundation  is  desired  with  sloping  sides,  the 
earth  can  be  undercut,  and,  unless  it  be  sandy,  the  sides  will  not 
crumble  to  any  great  extent. 

With  engines  above  200  h.p.  the  expense  of  a  wooden 
form  is  low  enough  to  justify  its  use  since  it  will  simplify 
the  work  of  excavation.  In  making  the  excavation  it  is  a  good 
policy  to  remove  enough  earth  around  the  foundation  proper  to 
accommodate  a  pipe  trench  or  chase.  The  use  of  a  chase  enables 
the  erector  to  place  all  the  water  and  oil  piping  out  of  sight  yet 
accessible.  This  method  of  pipe  disposal  is  far  superior  to  that, 
followed  by  many  erectors,  of  installing  the  pipe  in  the  floor, 
permanently  covering  it  with  concrete. 

After  removing  the  earth,  wooden  forms  are  next  installed, 
outlining  the  shape  of  the  engine  foundation.  A  form  often 

32 


INSTALLATION  OF  AN  OIL  ENGINE  33 

employed  is  made  up  of  1-inch  rough  lumber  nailed  to  2X4  in. 
studding.  Frequently  the  manufacturer's  draftsman  indulges 
his  fancy  in  giving  the  foundation  a  multitude  of  steps  and  angles. 
It  is  advisable  to  boldly  depart  from  all  unnecessary  shapes  and 
make  the  foundation  as  nearly  rectangular  as  possible.  $ome 
designers  claim  that  the  earth  pressure  on  the  foundation  steps 
eliminates  the  vibration  that  is  common  to  many  engines.  The 
total  earth  pressure  is  so  slight  that  the  results  secured  are  in- 
significant. The  proper  method  of  preventing  vibration  is  the 
use  of  generous  dimensions  in  the  footing  and  in  the  foundation 
proper.  Frequently  the  eradication  of  the  many  irregular  shapes 
entails  the  employment  of  more  concrete  than  otherwise,  but  it 
will  prove  cheaper  in  the  end.  Concrete  is  lower  in  cost  than 
the  carpenter  work  of  making  forms. 

In  locations  where  "made  ground"  is  encountered  it  becomes 
absolutely  necessary  to  provide  piling  under  the  foundation.  A 
very  common  practice  is  to  drive  two  rows  of  piles  10  to  20  feet 
long,  the  piles  being  some  8  feet  apart.  A  3-foot  diameter 
excavation  is  made  about  each  pile-head  2  or  3  feet  deep. 
These  round  holes  are  filled  with  concrete  as  the  foundation 
is  poured.  Such  a  plan  provides  a  secure  footing  that  will 
prevent  any  displacement  of  the  foundation. 

Establishing  Engine  Center  Line. — Before  pouring  the  con- 
crete, it  is  necessary  to  set  the  template.  In  the  majority  of 
installations  it  is  usual  to  have  the  engine  align  with  some  shaft 
already  installed.  The  proper  way  to  establish  the  engine  shaft 
center  line  is  by  the  use  of  an  engineer's  transit.  This  is  set  under 
the  existing  shaft  and  sighted  along  the  shaft.  Dropping  two 
plumb  lines  from  the  shaft  makes  the  locating  of  the  line  an  easy 
problem.  After  the  line  of  sight  is  established,  and  the  datum 
mark  made,  the  transit  is  turned  90  degrees  and  a  stake  set  along 
the  desired  engine  shaft  line.  Moving  the  transit  to  this  latter 
stake,  it  is  sighted  on  the  datum  stake  or  mark.  This  establishes 
a  line  of  sight  at  right  angles  to  the  line  shaft.  Turning  the  tran- 
sit 90  degrees  and  driving  a  stake  along  the  new  line  of  sight  gives 
two  points  in  a  line  parallel  to  the  datum  shaft.  After  these  two 
points  are  located,  a  strong  piano  wire  run  through  them  will 
indicate  the  desired  engine  shaft  center  line.  The  anchorage  for 
the  wire  ends  should  be  substantial  since  workmen  in  moving 
material  quite  often  strike  it, 


34  OIL  ENGINES 

Engine  Template. — Almost  all  manufacturers  furnish  the 
wooden  template  with  shaft  and  cylinder  center  lines  marked 
and  with  all  the  bolt-holes  bored  in  their  correct  positions.  When 
the  template  arrives  in  several  sections,  the  engineer  must  unite 
the  parts.  Extreme  care  must  be  used  in  this  assembling. 
It  is  advisable  to  lay  the  parts  on  a  level  floor,  and,  after 
squaring  up  the  center  lines,  the  sections  can  be  fastened 
together  with  screws. 

In  setting  the  template  above  the  foundation  excavation,  en- 
gineers use  devious  methods.  Some  block  up  the  wooden  form 
at  a  number  of  points.  This  is  indicative  of  shiftlessness  and 
lack  of  appreciation  of  the  work's  importance.  The  one  method 
that  is  free  from  criticism  is  the  use  of  two  heavy  timbers,  about 
12X12  in.,  to  which  are  bolted  cross  stringers  of  6X6  in.  The 
template  is  suspended  from  this  framing  by  bolts,  and,  if  the 
ends  of  the  12Xl2's  rest  on  solid  footings,  the  entire  framing  is 
rigid.  If  the  engine  is  of  medium  size,  8X8  in.  will  serve  for  the 
bearing  timbers.  Such  a  structure  will  not  move  in  event  a 
barrow  of  concrete  is  thrown  against  it. 

Foundation  Material. — The  proportioning  of  the  concrete  in- 
gredients varies  over  a  wide  range.  It  depends  to  a  considerable 
extent  upon  the  character  of  the  sand  and  gravel  used.  It  is 
obvious  that,  if  the  gravel  is  not  washed,  the  proportion  of  sand 
would  be  less  than  where  a  clean  gravel  was  obtainable.  For 
heavy  foundations,  such  as  the  one  under  discussion,  a  ratio  of 
one  part  cement,  two  parts  sand  and  four  parts  gravel,  or  crushed 
rock,  is  advisable.  This  mixture  possesses  ample  binding 
strength  and  is  free  from  the  danger  of  cracking  which  develops 
when  a  leaner  mixture  is  adopted.  In  order  to  lessen  the  foun- 
dation expense,  many  replace  the  gravel  or  crushed  stone  by 
broken  brick.  The  objection  to  the  brickbat  lies  in  the  danger 
of  serious  fractures;  furthermore,  unless  they  are  clean,  a  good 
bond  with  the  cement  cannot  be  secured.  Upon  pouring  the 
conglomerate  into  the  excavation  it  should  be  thoroughly 
rammed,  especially  at  the  corners.  Enough  water  should  be 
added  to  make  the  mixture  "  quaky." 

In  most  installations  the  process  of  pouring  the  foundation 
extends  over  a  period  of  several  days.  Each  night  the  surface 
should  be  given  a  thorough  wetting  down  to  prevent  any  pre- 
mature setting  during  the  night.  If  the  weather  is  cold,  an  old 
carpet  or  other  covering  can  be  placed  over  the  foundation  to  pre- 


INSTALLATION  OF  AN  OIL  ENGINE  35 

vent  freezing.  It  is  seldom  necessary  to  place  a  foundation  in 
freezing  weather,  but  when  such  conditions  do  exist  the  water 
used  should  be  warm,  and  a  liberal  covering  of  straw  and  old 
carpets  placed  over  it  each  night.  After  bringing  the  foundation 
to  the  desired  level,  the  surface  should  be  left  in  an  unfinished 
condition  and  dampened  each  night.  This  keeps  the  surface 
concrete  green  and  allows  a  good  finish  coating  to  be  applied 
after  the  erection  is  complete. 

Often  the  foundation  print  shows  no  reinforcing  steel.  With 
any  oil  engine  there  is  need  of  tie  bars  inserted  in  the  concrete. 
It  is  not  necessary  that  special  bars  be  purchased.  Old  steel 
rails,  discard  I-beams  and  the  like  are  just  as  serviceable.  A 
row  of  rods  or  bars  laid  longitudinally  with  crossbars  at  frequent 
intervals  for  a  reinforcing  matting  will  bind  the  entire  structure. 
The  steel  should  be  laid  about  halfway  from  the  base. 

Foundation  Bolts. — The  best  of  authorities  recommend  a 
foundation  bolt  tunnel  under  the  foundation  in  order  that  the 
bolts  may  be  placed  in  the  holes  after  the  frame  is  set  on  the 
foundation.  This  is  undoubtedly  an  excellent  plan  with  engines 
above  a  thousand  horsepower  capacity.  With  units  under  this 
size  the  results  obtained  do  not  justify  the  heavy  expense  of 
forming  the  tunnel.  The  same  objection  applies  to  the  design 
wherein  recesses  are  formed  in  the  concrete  at  the  base  of  the 
bolt  cavities. 

For  all  ordinary  installations  the  best  method  embodies  the 
employment  of  bolt  tubes:  3-inch  black  pipe  is  quite  satis- 
factory. When  such  an  arrangement  is  decided  upon,  the 
pipes  should  be  cut  to  a  length  equal  to  the  length  of  the  bolt 
from  bottom  washer  to  wooden  template.  After  the  pipes  are 
placed  upon  the  bolts  and  the  latter  suspended  from  the  wooden 
template,  it  is  advisable  to  wrap  the  pipes  with  a  strong  manila 
paper.  This  paper  prevents  the  pipes  from  being  gripped  by  the 
concrete,  allowing  the  pipes  to  be  withdrawn  after  the  concrete 
has  set.  After  the  engine  base  has  been  set,  the  space  between 
bolt  and  concrete  should  be  filled  with  neat  concrete. 

Insufficient  Foundation. — In  foundations  installed  for  some 
years  parts  that  are  exposed  to  oil  drippings  become  rotten. 
These  portions  should  be  cut  away  and  renewed  with  neat  con- 
crete. Frequently  the  foundation  proves  to  be  too  small  to 
adequately  support  the  engine.  It  then  becomes  necessary  to 
devise  ways  and  means  of  increasing  the  foundation  footings. 


36  OIL  ENGINES 

Some  engineers  merely  trench  around  the  old  footing  and  add  a 
few  feet  of  concrete.  Unfortunately  the  new  and  old  concrete 
always  fail  to  unite  with  any  measure  of  bonding.  The  only 
satisfactory  correction  of  this  foundation  trouble  is  "rafting." 
A  trench  should  be  dug  completely  around  the  engine  foundation ; 
the  bottom  of  the  trench  should  be  at  least  4  feet  below  the 
foundation  base.  Three  or  more  tunnels  about  4  feet  high  and 
6  feet  wide  should  be  driven  transversely  under  the  foundation. 
These  tunnels  connect  with  the  trench  and  are  filled  with  concrete 
as  is  also  the  trench.  If  the  vibrations  have  been  excessive, 
it  is  advisable  to  fill  the  tunnels  with  concrete  and  remove  the 
earth  from  between  the  tunnels,  filling  these  voids  with  concrete. 
This  increases  the  entire  foundation  depth  by  the  height  of  the 
tunnels.  The  footings  can  be  extended  to  any  desired  width. 
Many  instances  of  warm  bearings  on  engines  using  outboard 
bearings  are  directly  traceable  to  a  shifting  or  settling  of  the 
foundation. 

Vibration. — One  of  the  object  ions  voiced  against  the  installation 
of  a  Diesel  engine  in  an  office  building  is  the  vibration  so  often 
present  in  the  internal  combustion  engine.  There  is  no  adequate 
defense  against  this  charge,  for,  as  customarily  installed,  an  oil 
engine  sets  up  vibrations  that  can  be  felt  even  in  large  buildings. 

In  preparing  the  foundation  for  these  installations  a  layer  of 
felt  at  least  10  inches  thick  should  be  placed  over  the  entire 
bottom  of  the  foundation  excavation.  A  concrete  retaining 
wall  6  inches  thick  should  be  built  about  the  foundation.  This 
wall  serves  to  keep  the  earth  from  touching  the  foundation. 
A  wooden  form  for  the  foundation  is  then  placed  within  this 
retaining  wall.  The  form  can  be  made  of  2X4  in.  studding  and 
1X12  in.  rough  boards.  The  2  X4's  should  not  touch  the  retaining 
walls  but  should  be  supported  by  wedges.  After  the  concrete  is 
in  the  wedges  can  be  removed;  this  will  allow  the  wooden  forms 
to  be  dismantled.  The  distance  between  foundation  and 
retaining  wall  ought  not  to  be  less  than  8  inches.  With  this 
construction  the  foundation  is  not  bound  in  any  way  to  the 
building  and  the  layer  of  felt  will  absorb  all  the  shocks  incident 
to  the  engine's  operation. 

With  any  concrete  foundation,  after  the  engine  is  erected,  a 
heavy  coating  of  waterproofing  cement  mixture  makes  an  ideal 
finish.  This  coating  will  serve  to  keep  any  oil  from  seeping 
into  the  concrete. 


INSTALLATION  OF  AN  OIL  ENGINE 


37 


Installation  of  Engine  Frame  or  Bed. — The  frame  is  generally 
mounted  on  skids  when  shipped  from  the  factory.  To  unload 
this  heavy  section  entails  considerable  mental  and  physical  effort. 
The  easiest  method  involves  the  building  of  a  crib  against  the  end 
of  the  flat  car  with  a  runway  of  heavy  timbers,  such  as  12  X 12  in., 
laid  from  the  level  of  the  car  to  the  edge  of  the  engine  foundation. 
After  the  frame  has  been  jacked  up  and  rollers  inserted  under 
the  skids,  it  can  be  easily  pinched  to  the  incline.  A  rope  hitch 
should  be  run  to  the  end  of  the  car  and  about  the  car  axle  for 


I 


Recess  filled 
after  Frame  is 
in  Place 

-  -Jacff 


FIG.  24. — Setting  engine  on  foundation. 

the  purpose  of  restraining  the  motion  down  the  incline.  Since 
the  " runway"  has  been  carried  up  over  the  foundation,  clearing 
the  foundation  bolts,  the  frame  is  moved,  without  difficulty 
into  approximate  position  on  the  concrete.  In  many  instances 
a  winch  is  available,  which  reduces  the  labor  of  moving  the  heavy 
bed.  It  usually  is  necessary  to  employ  a  "dead  man,"  or  post, 
and  a  tackle  block.  The  next  step  is  the  placement  of  the  frame 
directly  on  to  the  concrete*  This  involves  the  use  of  at  least 
four  heavy  jacks,  one  at  each  corner.  These  jacks  can  be  located 
in  recesses  to  be  rilled  after  the  engine  is  set.  The  frame  is 
raised  a  slight  amount  and  the  skids  are  removed,  Fig.  24,  after 
a  number  of  iron  wedges  with  a  butt  thickness  of  about  % 


38  OIL  ENGINES 

inch  have  been  prepared  and  placed  on  the  foundation  along  the 
line  of  the  frame.  The  frame  is  now  lowered  and  rests  on  these 
wedges,  whereupon  the  jacks  are  removed.  The  wedges  are 
used  to  line  up  the  frame. 

As  the  frame  rests  on  wedges,  the  center  lines  of  the  engine 
should  be  established.  Since  the  stakes  used  in  locating  the 
center  line  of  the  template  are  still  in  place,  the  piano  wire  is 
run  between  the  two  stakes  and  through  the  bearing  housings. 
The  bed  can  be  shifted  until  the  wire  is  exactly  center.  The 
wedges  are  then  gradually  knocked  out,  bringing  the  frame 
down  on  to  the  foundation.  If  care  is  used  in  moving  the  wedges, 
no  shifting  will  occur. 

Leveling  up  the  Frame. — If  the  engine  is  a  horizontal  one,  it 
is  usually  possible  to  level  it  up  by  a  spirit  level  placed  on  the 
main  bearing  housings.  The  top  surfaces  of  the  housings  are 
machined  parallel  with  the  plane  of  the  crank  and  cylinder 
center  lines.  By  placing  the  level  parallel  with  the  shaft  line 
the  frame  can  be  trued  up  transversely,  while  placing  it  across 
the  top  of  the  two  throws  and  parallel  with  the  cylinder  allows 
the  discrepancy  that  exists  longitudinally  to  be  corrected.  It 
is  necessary  to  check  the  results  by  leveling  both  housings  and 
rechecking  the  process.  A  few  engines  have  a  true  surface 
machined  on  the  top  of  the  cylinder  jacket  to  facilitate  the 
work  of  leveling. 

After  the  frame  has  been  leveled,  the  foundation  bolt-nuts 
should  be  drawn  down  tight  and  a  thin  grouting  of  neat  cement 
poured  into  the  cavities  around  the  bolts  and  well  troweled 
under  the  frame.  If  this  coating  is  brought  up  above  the  bottom 
of  the  engine  frame  an  inch  or  so  and  sloped  toward  the  edge  of 
the  foundation,  the  appearance  of  the  installation  is  much  im- 
proved. The  iron  wedges  should  be  left  in  place.  In  event 
the  engine  settles  out  of  line,  these  wedges  facilitate  correcting 
the  trouble. 

With  a  vertical  box-frame  engine  a  sub-base  is  usually  provided. 
This  is  first  set  on  the  foundation  and  aligned  by  the  same  proced- 
ure. However,  while  the  bolts  should  be  drawn  up  snug,  the 
grouting  in  is  best  deferred  until  the  main  frame  is  set.  Where 
the  sub-base  is  used,  the  bottom  of  the  frame  is  usually  planed, 
and  the  frame  should  set  level  if  the  sub-base  has  been  properly 
aligned. 


INSTALLATION  OF  AN  OIL  ENGINE 


39 


Erecting  the  Cylinders. — All  horizontal  engines  are  shipped 
with  the  cylinder  liner  in  place;  it  follows  that  correct  alignment 
of  the  cylinder  is  secured  when  the  frame  is  properly  set.  With 
the  vertical  box-frame  engine  the  placing  of  the  cylinders  is  a 
ticklish  proceeding  and  calls  for  much  ingenuity  in  plants  where 
facilities  are  meager. 

Every  plant  should  be  equipped  with  an  I-beam  trolley  and 
differential  hoist.  This  hoist  should  be  of  at  least  5-ton  ca- 
pacity. The  I-beams  can  rest  on  brick  pediments  that  are  incor- 
porated in  the  building  walls.  In  case  such  equipment  is  not 
available,  it  becomes  necessary  to  construct  a  wooden  frame 


..-Frame  12*  12" 


Side  View 


FIG.  24A. — Scaffolding. 

similar  to  Fig.  24A.  The  top  beam  should  clear  the  frame  by 
at  least  10  feet  to  give  ample  room  for  the  blocks.  If  timbers 
of  sufficient  length  are  not  obtainable,  the  frame  can  be  made  of 
built-up  timbers  constructed  of  six  planks,  2X12  in.  in  size, 
lag-screwed  together.  Stout  planking  should  be  placed  along 
the  side  of  the  engine  to  prevent  the  cylinder  damaging  the 
frame  as  it  is  hoisted  to  the  top;  6X6  in.  cross  timbers  can  be 
laid  across  the  top  of  the  frame  to  act  as  a  landing  for  the  cylinder. 
These  timbers  guard  the  studs  against  damage.  The  tackle 
blocks,  or  chain  hoists,  are  fastened  to  the  cylinder  top,  and  it 
is  raised  until  it  can  be  lowered  on  to  the  6X6  in.  platform. 
It  is  always  advisable  to  use  two  blocks.  This  is  a  safety  meas- 
ure in  case  one  breaks.  After  the  cylinder  is  placed  on  the  plat- 
form, it  should  be  pinched  into  place  over  the  studs.  All  the 
timbers  save  two  outside  the  bolt  circle  can  be  removed.  By 


40  OIL  ENGINES 

lifting  the  cylinder  with  the  blocks,  which  have  been  centered 
above  the  cylinder,  the  two  timbers  are  withdrawn  and  the  cylin- 
der lowered  on' to  the  frame. 

After  the  cylinder  is  in  place,  a  plumb  bob  is  dropped  through 
it.  To  do  this  a  metal  or  wood  strip,  similar  to  Fig.  25,  is 
fastened  to  one  of  the  cylinder-head  studs.  A  washer  is  attached 
to  the  bob  line  after  the  line  has  been  passed  through  the  slot  in 
the  strap.  The  strap  is  placed  over  the  approximate  cylinder 
center.  The  slot  allows  the  bob  line  to  be  moved  until  it  is 
exactly  center.  To  center  the  plumb  line  at  the  top  of  the  cylin- 
der, a  pair  of  inside  calipers  are  used.  This  centering  calls  for 
the  greatest  patience  on  the  part  of  the  erector.  After  centering 


,*. 

*'  ±-   I 

"oj  ' 


:  .........  -3 


FIG.  25. — Centering  strip. 

the  line  at  the  top,  measurements  must  be  taken  at  the  bottom 
of  the  cylinder  to  ascertain  if  the  bob  line  is  central  at  this  place. 
Since  both  the  cylinder  flange  and  frame  top  are  machined  true, 
it  is  seldom  that  the  cylinder  does  prove  out  of  plumb,  providing 
the  frame  has  been  properly  set.  If  this  should  occur,  the  frame 
must  be  wedged  up  until  the  cylinder  center  line  is  plumb.  If 
the  engine  is  multi-cylindered,  a  plumb  is  dropped  through  each 
cylinder  and  kept  in  place  until  the  engine  shaft  is  lined  up, 
Fig.  26.  The  bob  lines  must  square  with  shaft  center  line. 
Practically  the  same  method  can  be  followed  with  the  A-frame 
engine. 

Centering  the  Shaft. — It  is  necessary  to  check  the  crankshaft 
bearings  to  insure  that  the  shaft  will  be  square  with  the  cylinder 
center  lines.  Two  metal  or  wood  strips,  Fig.  25,  should  be  fas- 
tened to  the  ends  of  the  engine  frame,  as  in  Fig.  26,  with  a  piano 
wire  stretched  between.  The  disks  should  be  moved  until  the 
horizontal  wire  just  touches  the  three  cylinder  plumb  lines;  the 


INSTALLATION  OF  AN  OIL  ENGINE 


41 


wire  should  be  leveled  at  the  same  time  with  the  spirit  level. 
The  bearings,  which  have  been  placed  in  their  housings,  should  be 
calipered  to  see  if  the  line  is  central  with  each  bearing.  If  a 
bearing  is  out,  then  it  must  be  shifted  until  it  registers  central. 
With  the  wedge-type  bearing  this  alteration  can  be  secured  by 
proper  movement  of  the  wedges.  If  the  bearings  are  of  the  non- 
adjustable  shell  type,  it  becomes  necessary  to  scrape  the  high 
bearing  and  shim  up  the  low  ones. 


FIG.  26. — Aligning  cylinders  and  shaft. 

Before  the  shaft  is  lowered  on  to  the  bottom  bearing  shells, 
small  lead  wires,  about  J^2  mcn  m  diameter,  should  be  placed 
along  the  bottom  of  each  bearing.  When  the  shaft  is  placed  in 
position,  these  wires  flatten  out.  By  raising  the  shaft,  these 
wires  can  be  removed  and  their  thickness  measured  by  a  mi- 
crometer. If  the  lead  is  of  the  same  thickness  throughout  its 
length,  the  shaft  evidently  bears  evenly  in  a  longitudinal  direc- 
tion. If  any  unevenness  is  present,  the  shell  must  be  scraped  to 
a  fit.  To  check  the  area  of  the  shell  which  is  supporting  the 
shaft,  the  shaft  can  be  coated  with  Prussian  blue  and  rotated. 


42 


OIL  ENGINES 


Upon  lifting  the  shaft  the  bearing  will  show  which  points-are  high 
or  low.  Scraping  the  babbitt  will  bring  the  surface  to  a  perfect 
contact. 

Many  erectors  have  the  habit  of  using  a  chain  sling  on  the 
shaft.     This  is  absolutely  out  of  place  with  a  Diesel  engine. 


8  Ply  rarrclt  tjecinctticn  Tar  &  Gravel  Hoofing  . 


SECTION  A-A  THROUGH  NEW  DIESEL  ROOM 


v          v         v          v         V 

FIG.  27. — Diesel  engine  room. 

Sacking  wrapped  about  the  shaft  and  the  use  of  rope  slings  will 
eliminate  all  danger  of  scoring  the  shaft.  It  requires  only  a 
small  dent  or  cut  on  the  journal  to  ruin  a  bearing.  In  han- 
dling the  shaft  it  is  advisable  to  suspend  it  by  slings  from  each 
end;  if  possible,  the  slings  should  be  tied  on  the  shaft  at  other 
than  journal  points.  If  no  traveling  crane  is  at  hand,  two 
wooden  forms,  such  as  indicated  in  Fig.  24,  can  be  constructed. 


INSTALLATION  OF  AN  OIL  ENGINE  43 

In  checking  up  the  alignment  of  an  engine  shaft  already  in- 
stalled, an  approximate  solution  is  by  placing  one  of  the  cranks  in 
a  horizontal  position,  which  can  be  done  by  using  a  spirit  level : 
placing  the  level  across  the  two  webs  will  prove  if  the  shaft  is 
out  of  line.  This  should  be  rechecked  by  reversing  the  level. 
This,  of  course,  is  only  possible  where  the  crank  throws  are 
milled  on  all  sides. 

With  an  engine  employing  an  outboard  bearing  the  alignment 
of  the  extension  shaft  merely  necessitates  the  continuation  of  the 
shaft  center  line.  In  erection  the  main  point  that  demands  the 
exercise  of  extreme  care  is  the  bolting  of  the  extension  shaft  to 
the  main  shaft,  or  to  the  flywheel,  as  the  design  may  be.  The 
flange  bolts  should  be  drawn  up  uniformly,  a  part  turn  of  each  nut 
in  succession.  Some  erectors  are  in  the  habit  of  bolting  the  two 
parts  together  with  the  outer  end  unsupported  by  the  outboard 
bearing.  They  then  turn  the  engine  over  and  adjust  the  outer 
bearing  against  the  shaft  end.  The  danger  here  lies  in  the  lia- 
bility of  the  unsupported  shaft  weight  throwing  it  out  of  level. 
Many  hot  outer  bearings  can  be  attributed  to  this  carelessness. 

Plant  Building. — The  design  of  plant  building  is  largely  deter- 
mined by  instrumentalities  beyond  the  sphere  of  the  engineer's 
influence,  though  the  layout  of  the  machinery  is  essentially  a 
matter  where  the  operator  should  be  considered.  Figure  27  is  a 
section  through  a  plant  containing  two  500  h.p.  units.  The 
figure  shows  the  method  of  piling  the  foundation-. 


CHAPTER  IV 
MAIN  BEARINGS.     CRANKSHAFTS 

TYPES,  ADJUSTMENTS  AND  REPAIRS 

Main  Bearings. — Diesel  engine  bearings  may  broadly  be 
divided  into  two  classes;  namely,  adjustable  and  non-adjust- 
able. The  former,  of  course,  embodies  the  addition  of  a  wedge 
and,  as  applied  to  the  vertical  type  engine,  is  outlined  in  Figs. 
7  and  23. 

Adjustable  Bearings  for  Vertical  Engines. — This  bearing  design 
is  found  mainly  on  the  older  engines,  such  as  the  American 
Diesel.  It  follows  gas  engine  practice  of  fifteen  years  ago.  At 
that  time  the  rapid  wear  of  the  main  bearings  seemed  to  demand 
some  form  of  adjustment.  It  is  now  apparent  that  the  trouble 
lay  in  excessive  bearing  pressures.  With  more  liberal  bearing 
area  this  difficulty  of  rapid  wear  has  largely  disappeared. 

In  the  hands  of  an  experienced  operator  the  adjustable  feature 
has  its  attractions.  It  is  well-nigh  impossible  to  have  three  or 
four  bearings  with  babbitt  liners  of  uniform  characteristics. 
The  babbitt  first  run  out  of  the  ladle  is  of  a  density  considerably 
higher  than  the  bearing  that  is  poured  last.  The  natural  result 
of  this  non-uniform  density  is  the  variation  in  the  bearing  wear. 
To  the  engineer  who  is  versed  in  the  finer  adjustments  of  a  Diesel 
engine  the  realignment  of  the  bearings  is  not  a  difficult  task. 
In  readjusting  the  bearings  the  first  step  is  to  remove  the  bearing 
tops,  then  thoroughly  wipe  off  the  shaft  and  bearings  after  the 
shaft  has  been  raised  by  a  jack  set  at  each  end  of  the  frame. 
After  the  shaft  is  lowered  on  to  the  bottom  bearing,  it  should  be 
aligned  by  using  a  spirit  level.  The  two  end  bearings  are  adjusted 
until  the  shaft  is  level.  The  inside  bearings  are  then  brought  up 
snug  against  the  shaft  by  means  of  the  wedges.  The  connecting 
rod  big-ends  are-  next  made  fast  and  the  clearance  of  each  cyl- 
inder measured.  Often,  when  the  engine  has  been  badly  out 
of  alignment,  the  readjustment  of  the  bearings  alters  the 
clearance  of  one  of  the  end  cylinders.  This,  of  course,  must  be 
taken  care  of  by  varying  the  thickness  of  the  shims  between  the 
connecting  rod  and  its  big-end. 

44 


MAIN  BEARINGS  45 

In  making  corrections  for  misaligned  bearings,  it  is  highly 
important  that  the  bearing  bolt  nuts  be  tightened  up  very 
snugly  and  a  lock  nut  provided.  The  same  applies  to  the  side 
set-screws  of  both  the  wedge  and  the  bearing  where  they  are  used, 
as  in  Fig.  7.  If  either  the  bolt  or  set-screw  works  loose,  the  bear- 
ing will  shift  sidewise,  allowing  the  shaft  to  bend  at  each  impulse. 
Many  shafts  have  been  fractured  because  of  this  unrestrained 
flexure.  Each  time  the  crankcase  is  opened  the  bearings  should 
be  examined  and  the  bolts  tightened. 

Adjustable  Bearings  on  Horizontal  Engines. — The  direction 
of  the  bearing  pressure,  due  to  the  explosion  in  the  cylinder, 
makes  the  adjustable  bearing  well-nigh  imperative  on  horizontal 
engines.  The  cylinder  pressure  against  the  piston  head  may  be 
said  to  act  in  three  directions.  Part  acts  in  a  vertical  direction 
against  the  cylinder  walls;  the  remainder  has  its  direction  along 
the  connecting  rod.  This  latter  force  is  separated  into  two  com- 
ponents, one  acting  tangentially  to  the  crank-pin,  producing 
rotation,  while  the  second  component  acts  against  the  lower  bear- 
ing in  a  direction  dependent  on  the  crank  position;  but  at  all 
points  on  the  outward  or  power  stroke  its  direction  falls  between 
the  horizontal  and  vertical  plane  of  the  lower  half  of  the  bearing. 
If  the  bearing  be  of  two-piece  construction,  the  wear  resulting 
from  this  bearing  pressure  cannot  be  taken  up.  The  bearing 
wears  oblong,  and  the  engine  soon  pounds. 

Means  must  be  provided  for  compensation  for  this  wear,  and 
the  quarter-box  designs  of  bearing  are  the  natural  selection. 
The  adjustable  or  quarter-box  design  may  follow  either  of  two 
types;  namely,  a  three  or  four-piece  bearing.  In  actual  opera- 
tion the  three-piece  is  as  satisfactory  as  is  the  four-piece  bearing. 
The  pressure  is  against  the  bottom  and  the  front  quarter,  con- 
sequently there  is  practically  no  wear  on  the  rear  or  cylinder  side 
of  the  bearing.  The  wear  on  the  bottom  is  usually  insignificant 
since  it  receives  but  little  pressure  other  than  that  due  to  the 
weight  of  the  flywheel  and  shaft.  The  front  quarter  experiences 
the  greatest  wear  and  must  be  given  constant  attention.  Ordi- 
narily it  will  be  found  that  the  two  main  bearings  do  not  wear  at 
a  uniform  rate.  While  the  wear  on  each  bearing  should  be  taken 
up  as  it  develops,  it  should  not  be  forgotten  that  the  lower  shell 
and  the  rear  quarter  also  require  attention.  Periodically  the 
shaft  should  be  realigned  and,  if  it  is  proven  out  of  line,  the  lower 
and  rear  shells  shimmed  or  wedged  up  the  proper  amount.  Since 


46 


OIL  ENGINES 


the  clearance  space  between  the  cylinder  head  and  the  piston  is 
small  in  the  Diesel  engine,  there  is  a  danger  of  excessive  compres- 
sion pressures  if  the  wear  on  both  front  and  back  quarters  is 
taken  up  by  the  front  quarter  only,  for  this  tends  to  throw  the 
shaft  toward  the  cylinder.  Usually  the  horizontal  engine  em- 
ploys an  extension  shaft  and  outboard  bearing.  This  outer 
bearing  along  with  the  main  bearing  adjacent  to  the  flywheel 
carries  the  weight  of  the  wheel.  The  flywheel  weight  on  this 
main  bearing  causes  more  rapid  wear  on  the  bottom  quarter 
than  on  the  other  main  bearing.  Realizing  this  the  operator 
should  see  that  the  bearing  does  not  become  low. 


FiO.  28. — National  Transit  Diesel  main  bearing. 

National  Transit  Diesel  Main  Bearing. — Figure  28  is  the  three- 
piece  bearing  used  on  the  National  Transit  Diesel.  As  will  be 
noted,  the  upper  part  of  the  bearing  is  babbitted  directly  on  to  the 
bearing  cap.  The  bottom  and  rear  quartjer  consists  of  a  single 
babbitted  shell  while  the  front  quarter  is  provided  with  a  wedge. 
To  avoid  the  danger  of  wedge-bolt  breakage,  the  bolt-head 
fits  into  a  circular  opening  in  the  wedge.  The  bolt  can,,  then, 
accommodate  itself  to  any  displacement  of  the  wedge.  The  lubri- 
cation is  effected  by  two  chain  oilers  which  dip  into  the  oil  cellar 
<?ast  in  the  housing. 

The  Snow  Oil  Engine  Main  Bearing. — This  engine  employs 
a  bearing  as  illustrated  in  Fig.  29.  The  lower  shell,  as  well  as  the 
two  quarter-boxes,  is  equipped  with  a  wedge.  The  top  quarter 
is  a  separate  shell  and  is  not  cast  directly  on  to  the  cap,  as  is  usual. 


MAIN  BEARINGS 


47 


The  engineer  will  find  that  the  bottom  bearing  wears  most  at  the 
edge  adjacent  to  the  front  quarter.  The  front  quarter  also 
wears  at  this  edge. 

It  should  be  a  rigid  rule  in  every  plant  where  oil  engines  are 
installed  that  no  adjustment  of  the  bearings  shall  be  made  while 


FIG.  29. — Snow-Diesel  main  bearing. 


FIG.  30. — Allis-Chalmers  Diesel  main  bearing. 

the  engine  is  running.  The  revolving  shaft  allows  the  bearings 
to  be  drawn  up  tighter  than  when  idle;  the  careless  operator  will 
likely  tighten  up  the  wedges  enough  to  occasion  a  hot  bearing. 
The  oiling  of  the  bearing  is  accomplished  by  means  of  a 
mechanical  lubricator  furnishing  stream  lubrication. 


48 


OIL  ENGINES 


Allis -Chalmers  Diesel  Main  Bearing. — A  four-piece  bearing 
has  been  adopted  by  the  Allis-Chalmers  Co.  and  appears  in  Fig. 
30.  The  lower  shell  rests  on  a  spherical-bottomed  pad  with 
the  idea  of  allowing  the  bearing  to  shift  to  conform  with  the  posi- 
tion of  the  shaft.  Since  the  shaft  has  but  one  true  position,  which 
must  be  maintained  if  the  operation  be  smooth,  the  spherical 
seat  is  not  absolutely  necessary.  In  shimming  up  the  lower 
shell,  the  liners  are  properly  placed  between  the  shell  and  pad. 
The  two  side  quarters  are  equipped  with  wedges,  while  the  top 
is  babbitted  directly  onto  the  cap. 

The  operator,  especially  if  he  has  had  previous  experience 
on  steam  engines,  should  remember  that  the  adjustment  must 
be  made  almost  entirely  by  the  front  wedge  and  not  by  both 
quarter-boxes  as  in  steam  practice.  The  wedge  bolts  are  of  a 
design  that  eliminates  any  danger  of  breakage.  The  oiling  is 
secured  by  stream  lubrication  from  a  mechanical  oil  pump. 


Top   Shell 
G.  31.  —  Main  bearing  Mclntosh  and  Seymour  vertical  Diesel. 


Two-piece  Main  Bearings.  —  In  vertical  engines  the  wedgeless 
bearing,  built  along  the  lines  of  Fig.  31,  is  a  common  practice. 
The  bearing  is  provided  with  a  ring  oiling  system  ;  '  generally 
two  rings  are  used,  and  the  lubricating  oil  is  carried  in  a  cellar 
in  the  bearing  housing.  Much  depends  on  the  rings  working 
freely.  Ruined  bearings  frequently  occur  where  the  rings 
cease  rotating,  leaving  the  bearing  without  oil.  With  this 


MAIN  BEARINGS 


49 


bearing  it  is  absolutely  imperative  that  the  oil  in  the  cellar  be 
maintained  at  a  high  level.  To  insure  copious  lubrication  the 
distance  between  oil  level  and  point  of  contact  of  ring  and  shaft 
should  be  as  small  as  possible.  It  is  self-evident  that  the  greater 
this  distance  is  made  the  smaller  will  be  the  amount  of  oil  which 
will  reach  the  shaft  since  there  is  a  longer  time  interval  to  allow 
the  oil  to  flow  back  down  the  ring.  The  same  reasoning  applies 
to  the  grade  of  oil  used.  If  it  is  fairly  free-flowing,  the  shaft  will 
receive  a  meager  supply.  The  same  type  of  bearing  is  adaptable 
to  the  use  of  a  chain  instead  of  a  ring  for  oiling  purpose.  The 
chain  should  always  be  of  brass  in  order  to  eliminate  any  grooving 
of  the  shaft.  It  is  to  be  remembered  that  this  brass  chain  will 
wear  and  break.  If  the  bearings  are  not  inspected  occasionally, 
a  broken  chain  may  cause  the  babbitt  to  be  ruined.  It  is  an 
easy  matter,  when  the  engine  is  stopped,  to  pull  a  loop  of  the 
chain  up  through  the  bearing  cap  and  run  the  entire  length 
through  one's  fingers.  Any  links  that  are  worn  thin  are  easily 
detected,  and,  if  many  links  are  in  a  bad  condition,  the  entire 
chain  should  be  renewed.  The  advantage  of  the  chain  oiler  lies 
in  the  greater  amount  of  oil  the  links  will  carry  to  the  shaft  over 
that  supplied  by  a  ring  oiler. 


FIG.  32. — Busch-Sulzer  Bros.  Diesel  main  bearing. 

Busch-Sulzer  Diesel  Main  Bearing. — The  same  general 
type  of  bearing,  Fig.  32,  with  a  pressure  oiling  system  is  found 
on  the  Busch-Sulzer  Engine.  With  this  design  the  top  and 
bottom  shells  are  identical  and  in  emergencies,  when  the  lower 
shell  wears,  the  bearing  may  be  reversed,  using  the  top  for  the 
bottom.  There  is  no  wear  on  the  top  shell,  and  a  worn  bearing 
can  be  used  here  for  a  time.  This  practice  should  not  be  main- 
tained continually  since  a  loose  fit  at  the  top  shell  may  cause  the 
shaft  to  whip  and  lift  upward. 


50 


OIL  ENGINES 


With  the  pressure  system  it  is  essential  that  there  be  a  good 
seal  between  the  shell  and  the  housing.  If  not,  the  oil  will 
escape  at  the  ends,  and  the  shaft  will  fail  to  receive  proper  lubri- 
cation. Ordinarily,  if  the  oil  passage  to  one  bearing  becomes 
clogged,  the  gage  on  the  oil-pressure  line  will  show  an  increased 
pressure.  If  another  bearing  is  worn,  thus  allowing  a  freer 
passage  than  usual,  it  is  possible  for  one  line  to  be  completely 
clogged  without  any  pressure  change  being  evidenced. 


FIG.  33. — McEwen  Diesel  main,  bearing. 

McEwen  Diesel  Main  Bearing. — Figure  33  shows  the  two- 
piece  bearing  of  the  McEwen  Horizontal  Engine.  Since  these 
engines  are  small-powered  per  cylinder,  the  two-piece  construc- 
tion offers  no  objection.  It  should  be  understood  by  the  operator 
that  the  shaft  pressure  will  wear  the  bearing  oblong  and  that  no 
adjustment  is  practical  beyond  the  removal  of  the  shims.  After 


FIG.  34. — De  La  Vergne  Diesel  main  bearing. 

the  wear  becomes  pronounced,  the  only  remedy  is  replacement 
of  the  worn  part.  The  oiling  is  effected  by  two  rings  which 
dip  into  the  oil  cellar  below  the  bearing. 

De  La  Vergne  Diesel  Main  Bearing. — The  De  La  Vergne 
Engines  use  a  two-piece  bearing,  as  appears  in  Fig.  34.  The 
bottom  and  top  halves  are  set  at  a  45-degree  angle  which  allows 


MAIN  BEARINGS  51 

the  pressure  to  bear  on  the  center  of  the  bottom  shell.  By 
removing  shims  from  between  the  two  shells  the  necessary 
adjustment  can  be  made. 

Aligning  of  Bearings. — In  lining  up  shaft  bearings  the  first 
step  is  to  establish  the  shaft  center  line,  using  a  fine  piano  wire. 
Next,  the  bottom  shells  are  placed  in  the  housings.  If  the  shaft 
is  9  inches  in  diameter,  the  shell  is  adjusted  until  the  radii  from 
all  points  on  the  shell  surface  to  the  center  line  are  4^  inches. 
Where  the  bearing  is  of  the  bottom-wedge  type,  it  is  easy  to  make 
the  adjustment.  If  the  engine  is  a  horizontal  one,  or  a  vertical 
engine  with  a  wedgeless  bearing,  the  only  way  to  raise  the  shell  is 


FIG.  35. — Fitting  main  bearings  shells  to  seats  in  baseplate. 


by  the  insertion  of  shims  between  the  housing  and  the  shell. 
Practically  all  manufacturers  bore  the  housings  true  to  a  test 
bar.  Figure  35  is  self-explanatory  as  to  the  method  of  truing 
the  housing.  It  should  never  be  necessary  to  shim  up  the  bear- 
ings of  a  new  engine.  When  an  engine  is  installed,  among  other 
records  the  engineer  should  make  note  of  the  thickness  of  the 
bearings,  including  the  cast-iron  shell  and  the  babbitt  lining. 
Then,  in  case  of  wear,  the  engineer  knows  exactly  how  much  he 
should  shim  up  to  bring  the  distance  back  to  the  original  value. 
The  variation  in  the  bearing  levels  should  not  exceed  .003  inch. 
If  more  than  this,  the  shaft  will  likely  spring  in  operation.  On 
engines  with  the  flywheel  mounted  on  an  extension  shaft  the 
wear  is  more  rapid  on  the  main  bearing  adjacent  to  the  flywheel. 
The  thoroughly  versed  erector  always  sets  this  bearing  from  .003 
to  .004  inch  higher  than  the  other  bearings.  This  allows  a  wear 
of  .006  to  .008  inch  before  the  bearing  becomes  too  low. 


52  OIL  ENGINES 

Because  of  the  initial  misalignment  this  particular  main  bearing 
always  runs  warmer  than  the  other  bearings.  Many  operators 
experience  a  great  deal  of  worry  over  the  temperature  condition 
of  this  bearing  when,  in  fact,  the  higher  temperature  actually 
indicates  that  the  bearing  is  in  proper  shape.  When  the  tem- 
perature becomes  lower  than  with  the  other  bearings,  it  can  be 
taken  as  evidence  that  this  bearing  has  worn  low  and  must  be 
raised. 

Babbitting  a  Bearing. — There  are  many  instances  where  a 
bearing  becomes  hot,  causing  the  babbitt  to  drag  and  cut;  yet 


Hardened  and  Ground 


Edges  and  Faces 
Ground. 

FIG.  36. — Bearing  scrapers. 

in  the  majority  of  cases  it  is  not  necessary  to  rebabbitt  this  bear- 
ing. The  proper  procedure  is  to  use  scrapers  made  of  old  files 
along  the  lines  of  Fig.  36.  The  babbitt  should  be  smoothed 
down  and  all  loose  and  damaged  metal  cut  out.  This  may  cause 
part  of  the  liner  to  be  so  low  that  it  fails  to  contact  with  the  shaft. 
This  is  not  objectionable  since  the  ordinary  shell  has  an  excess 
of  bearing  surface.  Where  the  damage  is  considerable,  a  new 
babbitt  liner  is  the  only  solution.  Under  these  circumstances  it 
is  first  necessary  to  melt  out  all  the  old  metal  by  placing  the  shell 
in  an  iron  pot  over  a  fire  until  all  the  babbitt  becomes  soft  enough 
to  flow  off  of  the  cast  iron. 

A  good  many  engineers  think  that  tinning  the  cast-iron  shell 
is  uncalled-for  labor,  but  it  does  guarantee  that  the  babbitt  will 
hold.  To  cast  the  new  liner  it  is  advisable  to  secure  a  cast-iron 
or  sheet-steel  plate.  The  two  halves  are  then  clamped  together, 
with  a  paper  separator  where  the  two  halves  meet,  heated  and 
placed  in  an  upright  position  on  this  plate,  inserting  an  asbestos 
sheet  between  the  shells  and  plate  to  prevent  the  babbitt  from 


MAIN  BEARINGS 


53 


adhering  to  the  plate,  Fig.  38.  The  mandril  may  be  either  of 
cold  rolled  steel  or  a  piece  of  pipe  about  an  inch  smaller  in  diam- 
eter than  is  the  engine  shaft.  The  shell  base  is  dammed  with 
fire-clay  to  avoid  any  leakage  of  the  molten  babbitt.  The  bab- 
bitt, which  should  be  of  new  metal,  is  now  heated  in  a  ladle  or 
cast-iron  pot  until  it  will  char  a  pine  splinter.  The  dross  that 
floats  on  the  surface  of  the  hot  metal  is  best  skimmed  off  before 
the  bearing  is  poured.  The  pot  should  contain  enough  metal 
to  fill  the  entire  cavity.  It  is  impossible  to  use  two  pourings  on 
a  bearing  for  the  two  will  not  unite.  Most  bearings  have  a  solid 


FIG.  37.  FIG.  38. 

Babbitting  a  bearing. 


end  fixed  off 
FIG.  39. 


babbitt  liner  for  the  top  of  the  bearing.  Since  there  is  practically 
no  upward  thrust,  all  that  is  required  is  sufficient  surface  to  pre- 
vent the  shaft  from  lifting.  To  save  babbitt,  it  is  a  good  plan 
to  fill  in  the  top  shell  with  fire-clay  with  the  exception  of  the  ends, 
where  space  must  be  left  for  about  2  inches  of  bearing  metal, 
similar  to  Fig.  37. 

The  bearing  is  now  cast  with  the  bore  an  inch  smaller  in  diam- 
eter than  the  shaft.  The  halves,  still  clamped  together,  are 
nbw  removed  from  the  plate  and  cleaned  of  fire-clay.  They 
should  be  placed  on  a  lathe  and  bored  out  to  exact  shaft  diameter. 
After  being  separated,  a  bevel  should  be  cut  along  the  parting 
edges  so  that  these  edges  do  not  tend  to  scrape  off  the  oil  as  the 
shaft  revolves.  It  is  of  no  benefit  to  peen  the  surface  of  the  bab- 
bitt. This  practice  is  likely  to  loosen  the  bond  between  the 
babbitt  and  cast-iron  shell.  After  boring  the  shell,  the  two  halves 
should  be  lightly  coated  with  Prussian  blue  and  placed  one  at  a 
time  on  the  shaft.  By  rotating  the  half  of  the  liner,  the  engineer 
can  note  the  high  spots  and  scrape  the  bearing  to  a  perfect  con- 
tact. This  scraping  is  a  tedious  affair,  but  the  resultant  long 


54  OIL  ENGINES 

life  of  the  bearing  justifies  the  labor.  Oil  grooves  of  ample  length 
should  be  cut  in  the  babbitt.  In  cutting  the  oil  grooves  none  of 
them  should  be  carried  to  the  edges  of  the  shells.  If  this  is  not 
observed,  the  open  ends  of  the  grooves  offer  too  free  a  passage 
to  the  oil;  consequently  but  little  oil  flows  over  the  babbitt 
surface. 

Frequently  the  housings  are  not  bored  exactly  true,  and  the 
bearings  are  a  trifle  cramped,  touching  the  shaft  on  only  a  part 
of  their  length.  To  guard  against  this,  a  new  liner  should  be 
examined  after  the  engine  has  been  run  an  hour  or  so  on  light  load. 
If  the  shaft  bears  only  partially,  scraping  the  high  end  will  bring 
all  the  surface  to  a  contact.  This  is  better  than  shimming  up 
the  low  end  since,  if  the  latter  is  done,  there  is  a  liability  of  the 
cast-iron  shell  fracturing  due  to  the  poor  support  it  receives.  In 
bolting  down  the  bearing  cap  the  nuts  should  be  drawn  up  snugly. 
In  no  case  is  it  desirable  to  loosen  up  on  the  bolts  from  the  lower 
shell  by  means  of  shims  or  separators.  These  must  be  of  the 
proper  thickness  to  allow  running  clearance  between  cap  and 
shaft.  This  clearance  can  be  .001  inch  per  inch  of  shaft  diameter. 
By  placing  lead  wire  Or  fuse  wire  between  the  cap  and  shaft,  the 
cap  can  be  drawn  up  as  tight  as  possible  by  the  bolts.  Removing 
and  measuring  the  thickness  of  the  wire  enables  the  engineer  to 
determine  the  proper  amount  of  shimming  that  is  necessary  be- 
tween the  two  bearing  halves  to  obtain  this  running  clearance. 

Hot  Bearings. — A  hot  bearing  is  a  trouble  that  every  engineer 
some  day  will  experience.  Generally  this  occurs  when  the  load 
is  heavy  and  when  a  shut-down  is  an  impossibility.  The  engi- 
neer must  maintain  his  presence  of  mind  even  though  the  bearing 
smokes.  It  is  an  all  too  common  practice  for  the  operator  to 
excitedly  douche  the  bearing  with  a  bucket  of  water.  This 
is  of  no  avail.  Water  is  at  best  a  poor  lubricant,  and  it  will 
merely  make  matters  worse  by  washing  off  the  little  oil  that 
does  cling  to  the  shaft.  The  water  strikes  the  shell  and  the  shaft; 
this  results  in  the  contraction  of  the  shell,  thereby  loosening  the 
babbitt.  Another  bad  practice  is  the  use  of  an  air  hose  in  a 
vain  endeavor  to  cool  the  bearing.  The  only  correct  procedure 
is  to  run  an  oil  pipe  or  hose  to  the  bearing  and  feed  a  heavy 
stream  of  cool  oil  through  the  inspection  hole  in  the  cap  directly 
on  to  the  shaft.  If  the  bearing  is  provided  with  an  oil  cellar, 
the  drain  cock  to  this  should  be  opened  and  the  oil  allowed  to 
flow  out  after  passing  over  the  shaft.  It  is  best  to  run  the  engine 


MAIN  BEARINGS 


55 


light  until  the  bearing  cools  off.  If  the  engine  is  arranged  to 
allow  a  cylinder  to  be  cut  out,  the  two  cylinders  adjacent  to  the 
hot  bearing  should  be  operated  idle,  with  the  exhaust  valves 
blocked  open.  This  relieves  the  damaged  bearing  of  part  of  the 
pressure  due  to  the  cylinder  explosion.  After  shutting  down, 
the  bearing  liners  should  be  examined  and  any  necessary  repairs 
made. 

Clearance  Between  Bearing  and  Crank-cheek. — Many  engines 
develop  considerable  side-play  in  the  crankshaft  after  being  in 
service  a  few  years.  This  is  attributable  to  excessive  clearance 
between  the  end  of  the  main  bearings  and  the  crank-cheeks  or 


FIG.  40. — Steel  ring  to  eliminate  shaft  side  play. 

throws.  Engines  of  different  makes  vary  as  to  the  allowable 
clearance,  but  .007  inch  is  a  representative  value.  If  the  clear- 
ance is  too  great,  the  remedy  is  to  tin  the  ends  of  the  bearing 
and  run  a  ridge  of  babbitt  around  these  ends,  Fig.  39.  Using 
a  file  and  scraper,  all  surplus  metal  can  be  removed  and  this 
ring  of  babbitt  reduced  to  the  desired  thickness.  This  will 
prevent  the  side-play  and  should  last  for  at  least  a  year  before 
requiring  renewal.  Still  another  method  is  the  employment 
of  a  sheet-steel  ring.  This  may  be  made  along  the  lines  of 
Fig.  40.  The  wings  at  the  side  provide  space  for  the  fasteners. 
Scored  Shafts. — There  are  occasions  when  an  engine  crank- 
shaft becomes  scored  to  a  serious  extent  or  worn  unevenly  at 
the  journals.  The  average  engineer  is  prone  to  think  that  a 
shaft  in  either  of  these  conditions  is  worthless  and  should  be 
removed  at  once.  When  the  damage  is  severe,  of  course  this 
is  necessary.  More  often  a  little  work  will  allow  the  engine  to 


56  OIL  ENGINES 

still  pull  its  load.  In  cases  of  scored  shafts  an  emery  stone 
will  serve  to  smooth  up  the  shafts,  finishing  with  a  scraper  and 
a  final  polish  by  lapping.  The  scores  do  not  cause  trouble  pro- 
viding the  edges  of  the  cuts  are  smoothed  off,  preventing  the 
babbitt  from  being  picked  up.  When  the  wear  is  uneven,  the 
bearing  shell  should  be  scraped  to  a  fit,  even  though  the  diameters 
at  the  two  ends  vary  to  a  marked  degree. 

Fractured  Crankshafts. — The  bogie  of  the  Diesels  when  first 
introduced  in  this  country  was  broken  crankshafts.     Undoubt- 
edly the  one  thing  that  proved  an  obstacle  to  the  introduction 
of  the  oil  engine  was  this  question.     There  were  a  few  isolated 
cases  of  fractured  shafts.     These  without  reservation  were  due 
to  one  of  two  things.     The  early  Diesel  operator  knew  but  little 
about  the  engine  and  believed  in  letting  well  enough  alone.     No 
attempt  was  made  toward  the  adjusting  of  the  various  parts. 
The   fuel   valve  frequently   got  out  of  order  and  opened  too 
early,   causing  preignition.     These  excessive  pressures  had  to 
be  relieved  by  some  means.     Often  the  head  gave  way,  but  at 
times  the  head  proved  stronger  than  the  shaft,  and  so  a  fractured 
shaft  was  the  result.     The  second  cause  was  the  failure  to  take  up 
the  wear  in  the  main  bearings.     Frequently  the  inside  bearings 
became  worn,  allowing  the  shaft  to  be  supported  by  the  two 
outside  bearings  only.     This  produced  a  deflection  in  the  shaft 
which  was  repeated  and  reversed  each  revolution.     Ultimately 
the  shaft  gave  way.     As  a  rule  the  break  occurred  between  the 
pin  and  the  web  or  throw.     More  liberal  fillets  at  this  point 
along  with  more  knowledge  acquired  by  the  engineer  has  elimi- 
nated this  danger.     Several  score  of  Diesel  plants,  to  whose 
records  access  is  had,  report  no  trouble  with  fractured  shafts. 
Hot    Bearings— Two-cycle    Engines. — The    horizontal    two- 
stroke-cycle  Diesels  are  as  free  from  bearing  trouble  as  are  the 
four-stroke  cycle   engines.     At   the  reversal  of  the  stroke  the 
bearing  pressure  is  somewhat  relieved,  thereby  allowing  the  oil 
to  form  a  film.     With  vertical  two-cycle  engines  the  constant 
downward  pressure  results  in  faulty  lubrication.     This  is  the 
cause  of  the  many  instances  of  hot  main  bearings.     The  operator 
must  maintain  vigilance,  seeing  that  the  oil  supply  is  ample, 
and  at  the  first  sign  of  a  hot  bearing  the  engine  should  be  shut 
down. 


CHAPTER  V 
CONNECTING-RODS 

TYPES  AND  ADJUSTMENTS 

The  Diesel  connecting-rod  shares  with  the  main  bearings 
the  questionable  honor  of  giving  the  operator  hours  of  worry. 
To  the  engineer  who  is  versed  in  steam  engine  practice  it  remains 
a  source  of  wonderment  why  even  the  smallest  amount  of 
connecting-rod  brass  wear  can  cause  such  heavy  pounding.  The 
cylinder  pressure  of  the  Diesel  at  the  moment  of  initial  com- 
bustion mounts  into  the  hundreds  of  pounds:  many  times,  on 
starting,  the  pressure  runs  as  high  as  750  Ibs.  per  sq.  inch  in  those 
engines  not  equipped  with  relief  valves.  The  pressure  is  in  the 
nature  of  a  hammer  blow,  even  where  the  fuel  valve  adjustment 
is  correct.  It  is  to  be  expected  that,  because  of  this  constant 
hammering,  the  wear  on  the  brasses  will  be  far  more  than  that 
which  occurs  in  the  steam  engine  where  the  steam  enters  the 
cylinder  in  a  less  violent  manner.  Furthermore,  a  condition 
of  brass  clearance  that  would  be  perfectly  acceptable  with  the 
steam  unit  cannot  be  tolerated  with  the  Diesel.  This  explains 
the  continual  brass  adjustment  that,  to  the  uninitiated,  seems  to 
indicate  that  the  engine  builder  had  failed  to  properly  manu- 
facture these  parts. 

American  Diesel  Engine  Co.'s  Connecting-rod. — The  first  Diesel 
manufactured  in  America  was  fitted  with  a  connecting-rod  similar 
to  Fig.  41.  This  gave  place  to  the  type  illustrated  in  Fig.  42. 
The  wedge  design  was  quite  prevalent  in  gas  engine  work,  and 
the  Diesel  builders  evidently  obtained  it  from  that  source. 

In  adjusting  the  piston-pin  bearing,  it  is  necessary  to  remove 
the  rod  from  the  piston.  To  reduce  the  clearance  resulting 
from  the  wearing  of  the  brass,  the  cap  is  unbolted  and  the  re- 
quired amount  of  shims  removed.  The  wedge  must  then  be 
brought  up  snug  against  the  pin.  Some  operators,  under  a 
mistaken  idea,  use  no  shims  or  separators,  depending  solely 
upon  the  wedge.  It  must  be  conceded  that  many  engines  have 
operated  fairly  successfully  under  this  condition.  However, 

57 


58 


OIL  ENGINES 


the  shims  serve  to  keep  the  two  bearing  halves  rigid,  and,  in  the 
event  wear  occurs,  the  play  of  the  two  halves  will  not  hammer 
the  wedge.  The  objection  to  this  form  of  wedge  is  based  on  the 
frequency  of  fracture  of  the  wedge  bolt.  The  wedge  has  a  steep 
angle,  and  the  end  thrust  against  the  bolt  is  of  considerable 
proportion.  The  break  usually  occurs  in  the  thread,  allowing 
the  wedge  to  shift.  A  remedy  for  this  can  be  obtained  by  reduc- 


FIG.  41. — American  Diesel  Co.  connecting-rod. 


Fia.  42. — American  Diesel  Co.  connecting-rod. 

ing  the  wedge  angle.  This,  of  course,  lessens  the  total  adjust- 
ment obtainable,  but  shims  can  be  interposed  between  the  wedge 
and  brass,  giving  a  further  lift.  . 

The  crank  or  big  end  follows  conventional  Diesel  lines  in 
being  of  the  marine  design.  The  housing  is  cast  steel  and  has  the 
babbitt  run  directly  on  its  inner  surface. 

Allis -Chalmers  Diesel  Connecting-rod. — An  improved  form 
of  the  wedge-type  rod  is  found  on  the  Allis-Chalmers  Diesel. 
This  rod  has  a  marine  crank  end  and  a  wedge-adjustable  piston- 
pin  bearing,  Fig.  43.  The  improvement  consists,  mainly,  in  the 
employment  of  adjusting  or  separating  set-screws  in  conjunction 
with  the  wedge.  In  taking  up  the  bearing  wear  the  set-screws 
are  slackened  off  and  the  wedge  brought  up  hard  against  the 
brass.  The  wedge  bolt  is  then  backed  off  an  eighth  of  a  turn  and 
the  set-screws  tightened.  These  set-screws  serve  to  separate 
the  two  bearing  shells  enough  to  provide  running  clearance 
between  the  pin  and  the  bearing.  This  design  enables  the  oper- 


CONNECTING-RODS 


59 


ator  to  correct  any  piston-pin  bearing  wear  without  removing 
the  rod  from  the  engine.  After  the  clearance  assumes  propor- 
tions beyond  the  capacity  of  the  wedge,  shims  can  be  inserted 
between  the  shell  and  the  wedge  block.  The  big-end  bearing 
follows  the  usual  marine  design;  the  babbitt  is  cast  .directly 
onto  the  housing  halves.  Separators  of  J^-inch  thickness  are 
placed  between  the  housings  when  the  bearing  is  bolted  together 
for  boring.  The  adjustment  is  secured  by  the  addition  or 
removal  of  separators. 


ADJUSTING  SETSCREW 


FIG.  43. — Allis-Chalmers  connecting-rod. 

Snow  Oil  Engine  Connecting-rod. — This  rod,  Fig.  44,  is  quite 
dissimilar  to  the  rods  used  on  other  American  engines.  The 
piston-pin  end  is  of  the  marine  type  while  the  big  end  is  provided 
with  a  wedge-adjustable  open-end  bearing.  The  engine  has  a 
crosshead  design  piston.  Consequently  it  is  not  necessary 


FIG.  44. — Snow  Diesel  connecting-rod. 

to  remove  the  pin  for  the  purpose  of  taking  up  the  wear  in  the 
bearing.  The  bearing  bolts  can  be  slackened  off  and  the  proper 
amount  of  shims  or  separators  removed.  Since  the  crosshead 
pin  is  large,  but  little  adjustment  need  be  made  on  this  end. 
Adjustment  at  the  piston-pin  end  reduces  the  connecting-rod 
length,  and  thereby  increases  the  compression  clearance  in  the 
cylinder. 

In  compensating  for  the  wear  at  the  big  end,  the  wedge  is 
taken  up.  Since  the  entire  pressure  acts  on  the  wedge,  the  bolts 
must  be  kept  snug;  also  there  must  be  no  binding  of  the  bolt 
if  fracture  at  the  thread  is  to  be  avoided. 


60  OIL  ENGINES 

McEwen  Diesel  Connecting-rod. — This  rod,  Fig.  45,  has 
both  ends  of  the  marine  type.  The  adjustment  follows  standard 
practice.  On  the  big  end  the  bolts  are  provided  with  set-screws 
to  prevent  turning.  These  set-screws  must  be  tightened  after 
each  adjustment.  It  should  be  understood  that  the  taking  up 
of  the  wear  by  removal  of  shims  shortens  the  connecting-rod. 
This  affects  the  compression  pressure  by  increasing  the  clearance 
between  the  piston  and  cylinder  head.  A  record  should  be  kept 
showing  the  distance  between  the  piston  head  and  cylinder 


FIG.  45. — McEwen  Diesel  connecting  rod. 

flange  when  the  piston  is  at  top  dead-center.  After  taking  up 
the  wear  in  the  pin  bearings,  the  engine  should  be  put  on  top 
dead-center  and  the  clearance  measured  again.  The  increase  is 
noted,  and  separators  of  the  same  thickness  as  the  clearance 
increase  are  inserted  between  the  rod  and  the  big-end  box.  The 
big-end  bolts  are  then  re  tightened.  This  applies  to  all  engines 
using  a  marine  big  end. 

The  Mclntosh  &  Seymour  Co.  employs  a  rod  of  similar  design. 


FIG.  46. — National  Transit  Diesel  connecting  rod. 

National  Transit  Diesel  Connecting-rod. — The  National 
Transit  Pump  and  Machinery  Co.  has  adopted  the  form  of  rod 
appearing  in  Fig.  46.  The  big  end  is  of  the  standard  marine 
type  while  the  piston-pin  end  is  solid  and  fitted  with  bronze  bearing 
shells.  The  wear  on  these  shells  is  compensated  by  the  adjusting 
screw  in  the  rod  end. 

In  correcting  this  pin  wear,  the  rod  is  removed  from  the  piston 
as  is  also  the  piston  pin.  The  pin  is  then  replaced  in  the  bear- 
ing and  the  required  amount  of  shims  inserted  between  the  two 


CONNECTING-RODS 


61 


halves,  whereupon  the  adjusting  screw  is  tightened.  The  pin  is 
then  driven  out  of  the  rod,  and  the  piston,  pin  and  rod  are 
reassembled.  If  the  pin  is  too  tight  in  the  brass,  after  being 
tried  out  by  swinging  the  rod,  the  process  must  be  repeated. 
Some  engineers  neglect  the  matter  of  the  shims,  but  it  is  not 
advisable. 

With  this  particular  rod,  since  the  big  end  does  not  admit  of 
the  use  of  separators  to  bring  the  rod  length  back  to  normal, 
this  correction  must  be  made  by  the  insertion  of  strips  or  shims 
between  the  piston-pin  lower  bearing  shell  and  the  rod. 


FIG.  47. — Busch-Sulzer  Diesel  connecting-rod. 

Busch-Sulzer  Bros.  Diesel  Connecting-rod. — The  rod  design 
of  this  engine  has  the  big  end  of  the  marine  type,  separate  from 
the  rod  itself.  The  piston-pin  end  is  solid,  having  phosphor 
bronze  bearing  shells  and  an  adjusting  screw,  as  outlined  in 
Fig.  47. 

The  method  of  taking  up  the  piston-pin  bearing  is  the  same  as 
with  the  National  Transit  engine.  Since  the  big  end  is  separate, 
the  rod  length  is  corrected  by  the  insertion  of  separators  between 
the  rod  and  the  big  end.  The  crank  pin  is  lubricated  by  a  drilled 
passage  in  the  shaft,  as  indicated  in  Fig.  186.  The  rod  is  drilled 
its  entire  length  and  the  piston  pin  receives  its  lubrication 
through  this  passage.  The  passage  in  the  rod  registers  with  the 
oil  line  in  the  crankshaft  once  per  revolution,  thus  obtaining  the 
proper  amount  of  lubricant. 


62  OIL  ENGINES 

De  La  Vergne  Diesel  Connecting-rod.— On  the  F.D.  Diesel 
engine  manufactured  by  the  De  La  Vergne  Machine  Co. 
the  rod  follows  the  lines  of  Fig.  48.  This  is  quite  like  the  two  rods 
last  mentioned.  The  unique  feature  is  the  drilled  passage  in 
the  center  of  the  rod  for  the  purpose  of  oiling  the  piston  pin. 
The  oil  is  picked  up  from  the  big-end  bearing,  and  the  ports  here 
must  be  kept  open.  It  is  possible  for  a  hot  big-end  bearing  to 
close  the  ports  with  flowing  babbitt.  This,  of  course,  results  in 
a  ruined  piston-pin  bearing. 


FIG.  48. — De  La  Vergne  connecting-rod. 

New  London  Ship  and  Engine  Co.  Connecting-rod. — The 
Nelseco  Vertical  Marine  Diesel  employs  a  connecting-rod  with  a 
marine  big  end  and  a  solid  piston-pin  end.  The  latter  end  has  a 
bronze  bushing  but  is  provided  with  no  means  of  adjustment.  If 
the  bushing  wears,  it  must  be  replaced  with  a  new  one;  in  an 
emergency  the  bushing  can  be  reduced  at  the  split  and  a  thin 
shim  interposed  between  the  bushing  and  the  walls  of  the  rod  end. 
This  rod  can  be  seen  in  Fig.  103. 

Big-end  Bearings. — No  matter  what  the  design  may  be,  the 
operator  some  day  is  confronted  with  the  problem  of  a  big  end 
that  insists  on  running  hot.  The  first  move  is  to  determine 
whether  the  lubrication  has  been  faulty.  In  the  majority  of 
cases  this  proves  the  origin  of  the  trouble.  Generally  the  oil  pipe 
or  passage  has  become  clogged  with  dirt  or  a  bit  of  waste.  The 
remedy  is  obvious.  There  is,  for  some  unknown  reason,  a  tend- 
ency for  the  big-end  bearing  to  wear  more  rapidly  at  one  end 
than  at  the  other;  or,  at  times,  both  ends  wear  while  the  center 
remains  in  its  original  condition.  This  " belling"  of  the  bearing 
permits  the  pin  pressure  to  be  distributed  over  a  rather  small 
area  of  the  brass.  This  produces  a  local  heating  that  forces  the 
babbitt  to  drag,  filling  the  oil  passages  and  grooves.  An  ad- 
ditional result  of  this  unequal  bearing  wear  is  the  scoring  of  the 
cylinder  on  one  side.  When  this  bearing  wear  has  occurred,  it 
is  imperative  that  the  babbitt  be  rebored  to  the  pin  diameter 
and  the  oil  grooves  cut.  Even  if  the  wear  seems  excessive,  it 
is,  as  a  rule,  possible  to  avoid  rebabbitting.  Part  of  the  shims 


CONNECTING-RODS  63 

between   the  bearing   halves  can  be  removed,  and  the  halves 
clamped  together  and  rebored  to  size. 

It  sometimes  happens  that  part  of  the  babbitt  cracks  and  drags 
around  the  pin.  This  results  in  heating  and  a  badly  scored  bear- 
ing. If  the  trouble  is  local,  the  rough  spots  can  be  smoothed  with 
a  scraper,  and  the  bearing  can  then  be  placed  in  service  again. 
In  all  instances  where  big-end  bearings,  become  so  hot  that  the 
babbitt  is  thrown,  the  engine  should  not  be  stopped  immedi- 
ately; rather,  the  load  should  be  taken  off  and  the  engine  turned 
over  very  slowly,  with  the  particular  cylinder  cut  out.  In  re- 
babbitting  rod  bearings  the  same  method  as  described  for  main 
bearings  can  be  followed.  The  babbitt  should  always  be  cut 
on  a  bevel  at  the  junction  of  the  two  halves.  The  oil  grooves 
should  not  extend  to  the  bearing  edges,  and,  when  a  pressure- 
oiling  system  is  used,  the  oil  grooves  should  be  eliminated  since 
they  allow  the  oil  to  escape  too  rapidly. 

Side-play  is  of  frequent  occurrence  in  Diesel  operation.  The 
best  method  is  to  tin  the  bearing  sides  and  run  a  collar  of  babbitt 
around  the  bore.  This  collar  must  be  turned  square  with  the  pin.. 
It  is  not  necessary  to  cover  the  entire  side;  consequently,  the  collar 
can  be  machined  parallel  with  the  side  of  the  big  end.  Another 
method  is  the  employment  of  sheet-steel  washers  between  the 
web  and  the  big-end  sides.  Inspection  of  the  connecting-rod; 
bearings  should  be  performed  at  least  every  three  months. 

Along  with  the  wear  of  the  big-end  bearing  occurs  the  wear  of 
the  pin.  In  old  engines,  which  have  seen  several  years  of  service, 
the  pins  may  become  flattened  on  one  side.  This  can  be  corrected 
by  filing  and  lapping,  but  it  is  a  task  requiring  great  care  and 
patience.  It  is,  ordinarily,  not  difficult  to  detect  a  worn  rod 
bearing.  The  engine  will  emit  a  thump  or  pound  both  on  the 
in  and  out  strokes. 

Pin  Clearance. — To  estimate  the  amount  of  clearance  neces- 
sary between  bearing  and  pin,  an  excellent  scheme  is  to  "jump" 
the  rod  with  a  bar.  If  a  slight  movement  can  be  felt,  the  big 
end  has  ample  clearance.  "Jumping"  the  piston  allows  one  to 
judge  the  piston-pin,  clearance.  Another  and  better  method  is 
to  tighten  up  the  piston-pin  bearing  until  the  connecting-rod  can 
be  barely  swung  back  and  forth  when  the  piston  is  suspended 
by  a  chain  hoist.  If  the  movement  is  free,  there  is  too  much 
clearance.  If  a  man  cannot  swing  the  rod  without  tilting  or 
moving  the  piston,  the  bearing  is  too  tight. 


CHAPTER  VI 
PISTONS  AND  PISTON  PINS 

General. — The  pistons  of  all  engines  properly  fall  into  two 
general  classes — Crosshead  and  Trunk  Pistons.  The  crosshead 
piston  is  usually  shorter  than  the  trunk  piston  and  is  provided 
with  a  crosshead  which  receives  the  side  thrust  due  to  the  an- 


FIG.  49. — Cross-section  of  Snow  oil  engine  employing  a  cross-head  type  of  piston . 

gularity  of  the  connecting-rod.  Figure  49  illustrates  this  type. 
With  the  trunk  piston  the  upper  end  of  the  connecting-rod  is 
supported  by  the  piston  pin,  which  is  fastened  in  the  piston. 
Consequently  the  piston  receives  the  side  thrust  which  is  taken 
up  by  the  crosshead  in  the  former  type.  The  engine  shown  in 
Fig.  7  employs  the  trunk  design  of  piston. 

The  American  manufacturers  of  small  and  medium  powered 
engines,  up  to  200  h.p.  per  cylinder,  have  with  fewr  excep- 
tions designed  their  engines  with  trunk  pistons.  Owing  to  the 
high  cylinder  pressures  of  the  Diesel  engine,  the  side  thrust  of 
the  piston  is  of  serious  consequence,  although  in  a  200  h.p. 
cylinder  the  piston  can  be  constructed  of  a  length  sufficient 
to  bring  the  side  pressure  within  reasonable  limits. 

64 


PISTONS  AND  PISTON  PINS  65 

Trunk  Pistons. — On  units  with  a  rating  beyond  200  h.p. 
per  cylinder  practically  all  builders  use  a  crosshead  design 
of  piston;  in  fact,  the  first  Diesel  built,  even  though  of  25  h.p., 
employed  a  crosshead,  and  the  present-day  trunk  piston 
is  actually  an  adaptation  of  gas  engine  practice.  The  trunk 
piston  possesses  certain  features  that  make  it  attractive  to  the 
average  operator.  Since  the  side  pressure  is  taken  by  the  piston, 
there  is  no  crosshead  shoe  to  adjust.  This  adjustment,  on  a 
Diesel,  must  be  made  with  a  degree  of  knowledge  possessed  by 
none  save  experienced  engineers.  A  guide  clearance  that  would 
be  quite  satisfactory  on  a  high-grade  steam  engine  will  prove 
entirely  too  liberal  with  the  oil  engine.  This  nicety  of  running 
fit  necessitates  constant  adjusting  of  the  crosshead  shoes.  The 
operator  should  understand  that,  beyond  the  pound  that  it 
occasions,  a  loose  crosshead  will  allow  the  piston  to  bind  in  the 
cylinder,  producing  heavy  scoring. 

The  trunk  piston  presents  a  problem  in  lubrication  that  does 
not  exist  with  the  crosshead  type.  The  side  thrust  is  borne  by 
the  trunk  piston  along  its  entire  length,  but  this  bearing  surface 
extends  over  only  a  portion  of  the  circumference.  This  rubbing 
area  must  be  positively  and  copiously  lubricated.  The  problem 
of  lubricating  a  surface  periodically  exposed  to  hot  cylinder  gases 
is  difficult.  If  the  cylinder  and  piston  are  not  oiled,  either  the 
piston  or  cylinder  liner  will  cut. 

Piston  Clearance. — Since  the  transverse  pressure  throws  the 
piston  against  the  bearing  side  of  the  cylinder,  the  clearance 
between  the  piston  and  cylinder  must  be  less  on  the  trunk  than 
on  the  crosshead  design.  This  is  evident  since,  with  the  trunk 
piston,  the  entire  clearance  exists  on  the  piston  opposite  to  the 
wearing  side.  On  the  crosshead  type  the  clearance  is  fairly  well 
distributed  around  the  piston;  consequently  a  clearance  between 
piston  and  cylinder  of  .007  inch  is  actually  a  clearance  of  .015 
when  the  engine  is  firing.  The  crosshead  piston  can,  then,  be 
allowed  a  greater  clearance  than  can  the  trunk  type.  This  ob- 
viates danger  of  piston  seizing  when  the  engine  is  stopped  after 
a  run. 

Crosshead  Piston. — The  crosshead  design  eliminates  the  heat 
difficulties  of  the  piston-pin  brass  which  are  so  often  present 
with  the  trunk  piston.  Opportunity  is  also  afforded  for  a  heavier 
reinforced  piston  head.  There  is  also  less  likelihood  of  the  piston 
fracturing  since  it  is  not  confined  at  the  pin  bosses.  The  cross- 

5 


66 


OIL  ENGINES 


head  and  tod  design  admits  of  an  oil  guard  at  the  front  end  of 
the  cylinder  thereby  preventing  the  throwing  of  lubricating  oil 
into  the  cylinder  with  the  consequent  carbonization.  The  drip- 
ping of  dirty  cylinder  oil  or  unconsumed  fuel  oil  into  the  crank 
case,  where  it  renders  unusable  the  bearing  oil  that  is  held  there, 
is  also  eliminated  by  this  design.  To  this  can  be  ascribed  the 
lower  lubricating  oil  consumption  of  the  crosshead  design  of  en- 
gine. These  manifest  advantages  are,  it  is  the  feeling  of  the 
majority  of  engine  builders,  offset  by  its  greater  complication 
of  parts  and  the  greater  necessity  for  intelligent  adjustments. 


Some  Engines  had 
x-'"  only  Oil  Ring 


FIG.  50. — American  Diesel  Engine  Co.  piston. 

American  Diesel  Piston  and  Pin. — This  engine  is,  of  course,  no 
longer  manufactured.  However,  many  of  these  older  engines 
are  still  in  service,  and  the  operator  should  be  as  interested  in 
it  as  in  more  modern  designs.  The  piston  has  a  flat  crown  or 
top  that  is  strengthened  by  ribs  which  extend  down  along  the 
sides  to  the  pin  bosses,  as  shown  in  Fig.  50.  The  bosses  are 
bored  taper  and  offer  support  for  both  ends  of  the  pin  which  are 
of  different  diameters.  The  pin  is  fastened  into  the  piston  by  a  * 
washer  and  lock-nut;  a  dowel  or  short  key  at  the  large  end  pre- 
vents any  turning  of  the  pin.  Since  the  latter  is  ground  to  a 
seat  in  the  bosses,  the  contact  is  highly  satisfactory. 


PISTONS  AND  PISTON  PINS 


67 


The  chief  difficulty  experienced  with  this  design  of  piston  is 
the  distortion  at  the  pin  bosses,  with  a  resultant  oval  shape. 
This  distortion  produces  severe  cutting  on  the  piston  sides  along 
lines  about  30  degrees  from  the  pin  axis.  It  is  at  once  appar- 
ent that  the  pin  holds  the  two  bosses  at  a  fixed  distance;  when  the 
piston  heats,  the  expansion  will  occur  along  the  weakest  section. 
Figure  51  outlines  the  points  a. a.  of  distortion.  The  pin  bearing 
is  oiled  by  the  splash  from  the  crank-case ;  consequently  no  oil 
passages  are  needed  in  the  pin . 


FIG.  51. — Piston  distortion  from  elongation  of  the  piston  pin.     ; 

I       ...L,:    •/  •        ^ 

The  number  of  rings  used  with  this  piston  varies,  ranging  from 
four  to  seven.  Frequently  one  of  these  pistons  is^ found  equipped 
with  two  rings  per  groove.  In  such  event,  the  first  step  toward 
the  elimination  of  ring  trouble  is  the  substitution  of  one  broad 
nng  in  each  groove. 

Busch-Sulzer  Type  B  Piston  and  Pin. — The  type  B  piston 
represents  the  modern  development  of  the  Diesel  piston  design. 
The  head  is  thick  to  better  resist  the  cylinder  pressure  and  is 
concave.  The  clearance  is  small,  and  it  has  been  necessary  to 
cut  away  the  edge  of  this  concave  to  afford  a  clear  passage  for 
the  gases  as  they  enter  or  depart  around  the  valves.  To  avoid 
distortion  of  the  walls  it  is  strongly  reinforced  by  girth  ribs. 
Seven  rings  are  used  about  the  upper  part  for  sealing;  a  single 
ring  is  placed  at  the  bottom  as  an  oil  wiper. 
-<The  chief  variation  from  the  usual  American  design  is  the 
water-cooling  of  the  head.  This  feature  is  clearly  shown  in 
Fig.  52,  although  the  water  piping  is  not  included  in  the  drawing. 


68 


OIL  ENGINES 


The  pipes  are  rigid  and  run  parallel  to  the  piston  axis  at  each 
side  of  the  connecting-rod.  The  lower  ends  slide  in  the  stuffing- 
boxes  which  are  connected  to  the  engine's  water-piping  system. 
This  telescopic  method  of  feeding  the  water  is  superior  to  the 
pantagraph  or  knuckle  form.  There  is  no  inertia  effect  of 
swinging  parts  as  with  the  latter  type.  The  stuffing-box  is 
much  easier  to  maintain  water-tight  than  is  the  knuckle.  Even 


FIG.  52. — Busch-Sulzer  type  B  piston. 


FIG.  53. — Mclntosh  and  Seymour 
Diesel  piston. 


the  telescopic  arrangement  will  in  time  give  trouble  from 
weeping.  In  the  Busch-Sulzer  the  crank-case  receives  all  the 
return  lubricating  oil.  For  this  reason  leaks  at  the  stuffing-boxes 
allow  water  to  mix  with  the  oil  returns,  practically  destroying 
the  lubricating  qualities  of  the  latter.  On  each  occasion  that 
the  engine  is  stopped,  the  crank-case  doors  should  be  opened 
and  the  water  connections  examined. 

The  piston  pin  is  tapered  at  both  ends  and  is  held  by  a  washer 
and  nut  as  outlined.  When  the  engine  has  been  in  careless  hands, 
the  pin  may  deform  the  bosses  to  such  an  extent  that  the  pin 
has  a  poor  bearing  at  the  ends.  It  then  becomes  necessary  to 


PISTONS  AND  PISTON  PINS 


69 


grind  the  pin  to  new  seats.  To  accomplish  this  the  dowel  key 
at  the  big  end  must  be  removed  to  allow  rotation  of  the  pin. 

Mclntosh  &  Seymour  Piston  and  Pin. — This  company 
followed  the  designs  of  their 
Swedish  associates  in  building 
the  piston  appearing  in  Fig.  53. 
The  head  is  concave  and  is 
strongly  reinforced  on  the  lower 
side  with  a  series  of  ribs.  These 
ribs  do  not  extend  down  along 
the  piston  walls,  which  are 
supported  by  a  set  of  girth  ribs. 
The  piston  pin  is  straight  and 
is  held  in  the  bosses  by  set-screws. 

Allis -Chalmers  Piston  and 
Pin. — The  first  Diesel  engines 
manufactured  by  the  Allis- 
Chalmers  Co.  had  pistons  of 
the  standard  one-piece  construc- 
tion. The  small  clearance 
maintained  between  the  piston 
and  cylinder  liner  made  this 
design  impractical,  and  it  was 
early  replaced  by  the  piston 
outlined  in  Fig.  54.  The  piston 
body  is  formed  of  high-grade  cast 

iron  and  is  provided  with  a  false  or  removable  head.  This  head  is 
of  nickel-steel,  which  develops  fractures  at  a  much  slower  rate 
than  does  cast  iron,  and  is  held  in  a  machined  recess  by  the  stud 


FIG.     54. — Allis-Chalmers     Diesel 
section  of  piston. 


FIG.  54a. — Allis-Chalmers  Diesel  piston. 

shown.  The  piston  head  is  conical  in  shape,  and  the  impinge- 
ment of  the  fuel  charge  is  localized  at  the  center  of  the  nickel- 
steel  head.  This  construction  enables  the  builder  to  give  a 


70  OIL  ENGINES 

very  small  clearance  between  the  piston  and  cylinder  without 
danger  of  piston  seizing  due  to  head  expansion.  The  compres- 
sion is  sealed  by  six  rings  while  an  oil-wiper  ring  is  used  at  the 
base.  To  avoid  the  trouble  of  lubricating  oil  depositing  on  the 
inner  side  of  the  piston  head  and  forming  a  hard  scale,  a  baffle 
plate  is  incorporated  in  the  casting.  This  plate  is  in  two 
parts  which  allows  a  circulation  of  air.  While  this  plate  is 
fairly  effectual  in  maintaining  a  clean  head,  oil  will  deposit  on 
the  inner  walls  of  the  piston,  as  in  all  horizontal  engines. 

The  piston  or  gudgeon  pin  is  "hardened  and  ground.  The 
ends  fit  into  straight  bearings  in  the  bosses,  the  piston  being 
fastened  by  set-screws  which  are  locked  by  smaller  set-screws. 
The  lubricating  oil  for  the  pin  is  deposited  in  a  trough  at  the 
front  edge  of  the  piston,  from  whence  it  flows  through  a  passage 
to  the  end  of  the  pin.  The  pin  is  drilled  on  its  upper  surface 
to  permit  the  oil  to  issue  onto  the  bearing  surface. 

McEwen  Diesel  Piston  and  Pin. — McEwen  Bros,  use  a 
conical  head  piston  of  one-piece  construction,  Fig.  55.  The 
head,  after  being  cast,  is  annealed  for  the  purpose  of  removing 
all  casting  strains.  Six  rings  are  employed  to  hold  the  compres- 
sion while  the  wiper  ring  at  the  bottom  has  been  dispensed  with 
and  a  series  of  grooves  made  to  replace  this  ring.  The  pin  is 
held  by  a  set-screw. 

Snow  Diesel  Engine  Piston. — The  Snow  Engine  has  a  piston 
that  is  a  radical  departure  from  the  usual  design  with  four-stroke- 
cycle  engines.  The  piston,  as  seen  in  Fig.  56,  is  a  single  barrel 
casting  with  a  separate  steel  head  which  is  concave  on  its  surface. 
The  front  end  is  bolted  to  the  crosshead  yoke.  The  crosshead  is 
provided  with  a  single  shoe  and  has  a  wrist  pin  of  extra  large 
dimensions.  There  is  a  decided  advantage  in  the  crosshead  de- 
sign since  the  pin  size  is  not  restricted  as  it  is  in  the  trunk  piston. 

In  removing  the  piston  from  the  cylinder,  it  is  not  necessary 
to  dismantle  the  entire  head  and  valve  rigging.  The  connecting- 
rod  can  be  unbolted  from  the  crank  pin,  and  the  piston  with- 
drawn through  the  frame.  It  is  very  essential  with  the  crosshead 
piston  that  the  shoe  be  properly  adjusted.  The  engineer  should 
measure  the  thickness  of  the  shoe  when  first  installed  and  en- 
deavor to  maintain  this  dimension  by  the  insertion  of  shims. 

The  Standard  Fuel  Oil  Engine  Piston.— The  Standard  Fuel 
Oil  Engine  is  of  the  two-cycle  design  and  has  a  stepped  piston, 
outlined  in  Fig.  63.  The  main  or  power  piston,  Fig.  57,  is  a 
two-piece  barrel  casting.  The  head  is  conical  and  extends 


PISTONS  AND  PISTON  PINS 


71 


FIG.  55. — McEwen  Diesel  piston. 


FIG.  56. — Snow  Diesel  piston  cross-head  type. 


FIG.  57.— Standard  Fuel  Oil  Diesel.     Power  piston. 


72  OIL  ENGINES 

down  over  the  piston  body  forming  a  water-cooling  compartment. 
The  water  lines  are  passages  cored  in  the  main  piston  casting 
and  are  connected  to  telescopic  tubes  at  the  front  end.  The 
power  piston  is  bolted  to  the  enlarged  scavenging  piston.  The 
scavenging  piston,  in  the  60  h.p.  engine,  is  30  inches  in  diameter 
and  is  strongly  ribbed.  The  piston  or  gudgeon  pin  is  bolted 
to  this  piston,  consequently  the  latter  acts  as  the  cross-head  and 
receives  the  transverse  thrust  of  the  piston. 

Since  the  crank-case  does  not  act  as  the  return  lubricating 
oil  receiver,  leaks  in  the  water  tubes  are  not  so  serious  as  with  the 
vertical  engines.  The  water  stuffing-box  glands  must  be  kept 
tight  or  the  seeping  water  will  destroy  the  lubrication  on  the 
walls  of  the  scavenging  piston.  The  cooling  water  discharge 
must  be  kept  below  120°,  and  the  line  should  be  vented  to  avoid 
steam  pocketing  at  the  lower  edge  of  the  piston  head,  which 
receives  a  great  amount  of  heat  as  the  exhaust  gases  pass  out 
through  the  ports. 

Seized  Pistons. — Even  with  the  modern  types  of  pistons 
now  in  use,  many  plants  have  experienced  trouble  with  seized 
pistons.  This  difficulty  is  directly  traceable  to  either  of  two 
conditions.  One  of  these  is  insufficient  clearance  between  the 
piston  and  liner.  This  applies  especially  to  the  clearance 
around  the  piston  immediately  below  the  head.  The  temperature 
of  the  piston  head  must  run  very  high  to  establish  a  heat  balance 
wherein  the  heat  thrown  off  equals  the  heat  absorbed  by  the 
piston.  This  heat  condition  causes  the  head  to  expand  diamet- 
rically. If  there  is  insufficient  clearance  between  the  head  and 
cylinder  walls,  seizing  will  occur.  To  obviate  this  the  piston  can 
be  slightly  tapered,  with  a  decreasing  clearance  downward 
toward  the  piston  pin.  The  maximum  clearance  can  be  as 
great  as  }{Q  inch,  while  the  clearance  in  the  neighborhood  of  the 
first  piston  ring  should  be  approximately  .007  inch.  Another 
solution  of  head  expansion  is  found  in  the  conical  piston  head. 
This  conical  surface  possesses  ample  side  clearance  for  expansion. 
Incidentally,  the  conical  head  assists  in  the  thorough  interming- 
ling of  the  air  and  atomized  fuel  as  they  leave  the  injection  valve. 
The  same  relief  from  seizing  is  attained  by  the  dished  or  concave 
head.  This  design  of  head  also  serves  as  an  aid  in  mixing  the 
air  and  fuel. 

It  is  apparent  that  piston  seizing  when  it  is  due  to  lack  of 
clearance  can  be  eliminated  by  taking  a  small  taper  cut  off  the 


PISTONS  AND  PISTON  PINS  73 

piston  immediately  below  the  head.  The  taper  may  well  start 
between  the  top  pair  of  rings.  Certain  cast  irons  continue 
to  grow  even  after  the  clearance  has  been  increased  by  such  a 
cut.  It  then  becomes  necessary  to  watch  this  piston  and  repeat 
the  tapering  process  as  required. 

The  second  and  more  common  cause  of  seizing  or  freezing 
of  the  piston  is  lack  of  cooling  water.  This  may  occur  both 
while  the  engine  is  in  operation  and  after  it  is  shut  down.  The 
former  is  evidenced  by  the  loss  of  power  and  decrease  in  the  engine 
speed  and  usually  happens  on  a  change  from  light  to  heavy  load. 
The  average  operator  understands  that  on  full  load  the  quantity 
of  cooling  water  required  is  greater  than  on  the  lower  loads. 
As  the  load  comes  on,  the  usual  practice  is  to  increase  the  flow 
of  the  cooling  water.  This  chills  the  cylinder  liner  and  causes  it 
to  contract  before  the  hot  piston  experiences  any  effect  from 
this  additional  cooling  medium.  This  contraction  lessens  the 
working  clearance;  the  piston  becomes  hotter  and  ultimately 
grips  the  liner  walls.  The  remedy  is  to  decrease  the  amount 
of  cooling  water  as  the  heavy  load  comes  on;  then,  after  the 
cylinder  liner  warms  up,  the  flow  of  water  can  be  gradually 
increased  while  the  discharge  temperature  is  kept  fairly  constant. 

There  are,  also,  occasions  when  the  seizing  can  be  attributed 
to  a  hot  piston  pin,  and  ordinarily  this  is  noticeable  on  starting 
the  engine.  After  an  engine  has  been  in  operation  for  some 
minutes,  the  heat  absorbed  by  the  piston  is  equaled  by  the  heat 
given  off  by  the  piston  to  the  cylinder  walls,  etc.  The  heat 
contained  in  the  piston  when  the  engine  is  shut  down  is  large. 
If  the  flow  of  cooling  water  is  discontinued  at  once,  this  heat  is 
slowly  radiated  and  a  great  part  is  absorbed  by  the  piston 
pin.  The  pin  elongates  as  a  result  of  this  heat  absorption.  The 
end  thrust  of  the  pin  produces  a  change  in  the  shape  of  the  piston 
walls;  especially  is  this  true  when  the  walls  are  not  strongly 
ribbed.  The  deformation  of  the  piston  occurs  along  the  thinnest 
sections,  which  commonly  are  at  the  junction  of  the  pin  bosses 
with  the  piston  walls.  These  ridges  or  deformations  produce 
severe  cutting  of  the  cylinder  walls.  Many  liners  are  ruined 
by  this  action.  When  this  misfortune  is  experienced,  the  sole 
relief  other  than  piston  replacement  is  the  filing  of  the  high 
spots  until  the  piston  is  again  cylindrical.  The  surface  can  then 
be  dressed  by  emery  cloth.  Filing  will  also  smoothen  the  scored 
cylinder  walls.  A  quick  and  efficacious  repair  can  be  accom- 


74  OIL  ENGINES 

plished  by  first  dressing  down  the  rough  places  with  a  fine 
emery  wheel,  say  80 J  grade,  held  in  the  hand,  finishing  with  a 
file  and  emery  cloth.  To  some  this  probably  seems  a  radical 
treatment,  but  extensive  experience  on  many  scored  pistons  and 
cylinders  tends  to  prove  that  this  is  an  effective  way  to  rectify 
the  damage.  If  the  engineer  is  careful  in  using  the  emery 
cloth,  the  cylinder  and  piston  can  be  made  as  smooth  as  when 
new. 

Piston  seizing  is  at  times  in  evidence  when  turning  the  engine 
over  at  the  beginning  of  a  run.  If,  at  the  close  of  the  last  run. 
the  cooling  water  was  shut  off  too  early,  the  heat  in  the  piston 
head  may  evaporate  all  the  lubricant  on  the  piston  pin.  As  the 
dry  bronze  bearing  absorbs  the  heat,  it  cannot  expand  outward 
because  of  the  greater  mass  of  the  connecting-rod  end.  The 
bearing  closes  in  on  the  pin,  which  is  also  expanding;  this  action 
results  in  a  gripping  of  the  pin  that  is  not  completely  loosened 
even  after  the  parts  have  cooled.  On  starting,  this  wedged  bear- 
ing restrains  the  motion  of  the  connecting-rod,  and  the  engineer 
calls  it  a  seized  piston,  though  it  actually  is  a  case  of  a  seized 
piston  pin. 

Piston  Wear. — The  wear  of  the  piston  is  due  to  lack  of  lubrica- 
tion, deformation  and  the  natural  abrasive  action  that  results 
when  two  surfaces  rub  together.  The  lack  of  lubrication  can  be 
attributed  to  the  carelessness  of  the  operator.  No  matter  what 
manner  of  oiling  system  is  used,  the  engineer  is  never  blameless 
when  it  fails  so  far  as  to  wear  or  cut  the  piston. 

The  natural  abrasive  action  requires  years  before  the  wear 
assumes  such  proportions  as  to  necessitate  a  replacement.  A 
piston  should  last  from  four  to  eight  years  dependent  on  the 
hours  of  service  and  on  the  degree  of  intelligent  care  it  receives. 
It  is  impossible  to  set  a  hard  and  fast  rule  as  to  the  clearance  that 
can  exist  before  replacement  is  imperative.  A  vertical  trunk  or 
horizontal  crosshead  type  piston  should  have  a  clearance  of 
around  .007  inch,  while  the  horizontal  trunk  piston  should  have 
still  less.  In  operation,  if  the  rings  are  in  good  shape,  a  piston 
will  hold  the  compression  quite  satisfactorily  if  these  values  are 
doubled.  With  the  clearance  question,  as  with  many  Diesel 
problems,  the  engineer  must  allow  the  engine's  performance  to 
guide  his  actions. 

Piston  Rings. — The  customary  designs  of  rings  have  lapped 
ends  and  are  constrained  from  shifting  in  the  groove  by  dowels. 


PISTONS  AND  PISTON  PINS 


75 


Some  builders  fasten  the  ring  ends  together  with  a  pin.  It  is 
doubtful  whether  this  serves  any  useful  purpose.  In  turning  up 
new  rings,  the  casting  should  be  made  from  gray  cast  iron  free 
from  scrap.  The  outside  of  the  ring  is  machined  to  size.  Then 
the  casting  is  chucked  J^2  inch  out  of  center  and  the  inside 
turned,  the  ring  next  being  cut  off.  This  produces  a  ring  of  a 

r 


Removed  iv  bring  . 
Diameter  fo/4" 

FIG.   58.— Piston  ring  lap. 

varying  thickness  and  gives  an  almost  uniform  pressure  entirely 
around  its  circumference.  The  outside  diameter  of  the  ring 
should  be  %Q  inch  greater  than  the  cylinder  bore  of  the  engine. 
In  cutting  the  lap,  the  clearance  is  best  made  about  $>{$  inch, 
while  the  lap  may  be  as  much  as  1  inch.  The  lap  can  be  drilled 
and  then  cut  out  with  a  hack-saw,  as  shown  in  Fig.  58.  The 
edges  of  the  ring  are  left  square  and  should  never  be  rounded  as 
is  practiced  by  many  engineers. 


FIG.  59. — Fractured  piston  head. 

Fractured  Piston  Heads. — The  cracks  that  develop  in  the 
piston  head  can  be  placed  in  two  classes;  namely,  those  which 
take  a  circular  form  and  appear  around  the  base  of  the  concave 
portion  of  the  head,  and  those  fractures  which  are  radial  in 


76 


OIL  ENGINES 


direction.  The  former  are  caused  by  heat  strains  with  a  conse- 
quent breathing  action  at  the  base  of  the  cone.  These  fractures 
seldom  prove  serious,  and  it  is  possible  to  continue  to  operate  the 
engine  without  piston  replacement.  At  times  these  fractures 
appear  in  conjunction  with  cracks  on  the  interior  side  of  the  pis- 
ton head,  across  the  reinforcing  ribs.  In  such  cases  the  entire 
head  may  give  way. 

The  really  serious  fractures  are  those  that  develop  radially  in 
the  head.  Often  these  cracks  extend  across  the  head  some  6 
to  10  inches,  Fig.  59.  The  danger  lies  in  the  now  non-rigid 
head  allowing  the  piston  to  distort,  scoring  the  cylinder  walls. 


FIG.  60. — Sewing  fractured  piston  head. 

When  the  fracture  is  only  a  few  inches  in  length  it  can  be  re- 
paired by  "sewing. "  A  hole  should  be  drilled  at  each  end  of  the 
crack  to  prevent  any  further  development.  A  series  of  j^-inch 
holes  are  drilled  and  tapped  along  the  line  of  the  fracture.  Into 
these  holes  threaded  brass  plugs  should  be  inserted  and  cut 
smooth  with  the  surface.  Between  these  plugs  a  second  row  is 
inserted,  lapping  over  the  first  plugs.  This  entire  line  of  plugs 
is  then  hammered  smooth;  see  Fig.  60.  This  " sewing "  has 
been  practised  with  success  on  pistons  as  large  as  18  inches  in 
diameter. 


PISTONS  AND  PISTON  PINS  77 

Piston  Ring  Troubles.— Beyond  an  occasional  broken  ring 
the  only  difficulty  that  the  operator  will  experience  is  the  gum- 
ming of  the  rings  in  the  grooves.  The  gumming  may  be  pro- 
duced either  by  an  excessive  amount  of  fuel  oil  which  remains  in 
the  cylinder  in  an  unconsumed  condition  or  by  an  overabundance 
of  lubricating  oil.  The  solution  of  the  latter  trouble  is  simple; 
all  that  need  be  done  is  the  reduction  of  the  quantity  supplied. 
If  the  oiling  is  accomplished  by  a  mechanical  pump,  the  control 
can  be  readjusted.  If  the  engine  has  splash  lubrication,  the 
oil  level  can  be  lowered,  thereby  preventing  undue  throwing 
of  the  oil  emulsion  on  to  the  cylinder  walls.  Where  the  trouble 
is  traceable  to  excessive  fuel  oil,  the  problem  is  not  as  simple 
of  solution.  It  is  apparent  that,  in  such  cases,  the  difficulty 
lies  in  the  fuel  valve.  The  timing  may  be  incorrect,  or  the  air 
pressure  too  low  or  too  high,  or  the  atomizer  disks  or  cones 
may  be  out  of  order.  It  becomes  necessary  to  try  various 
experiments  until  the  proper  remedy  is  obtained. 

The  rings  can  be  loosened  by  soaking  the  entire  piston  in 
kerosene  or  lye  water,  after  which  the  rings  can  be  pried  off. 
In  removing  the  gum  and  carbon  a  copper  or  brass  scraper  should 
be  used.  It  is  not  advisable  to  clean  with  emery  paper  as  long 
as  the  piston  is  perfectly  smooth.  Each  time  the  engine  is  laid 
up  for  a  few  hours  a  small  quantity  of  kerosene  should  be  in- 
jected into  the  cylinder  through  the  air  admission  valve.  This 
kerosene  will  remove  any  carbon  on  the  piston  and  rings  that 
is  in  the  process  of  formation.  The  exhaust  valve,  in  such  event, 
is  best  blocked  open  to  allow  the  vapor  to  escape. 

Grinding  Taper  Piston  Pins. — A  number  of  engines  have 
piston  pins  with  taper  ends.  The  tapered  ends  fit  into  ground 
seats  in  the  piston  bosses.  The  ground  seats  gradually  pounds 
out  of  round,  forcing  the  engineer  to  regrind  the  pin  to  new 
bearings.  To  accomplish  this  with  the  minimum  of  trouble 
the  piston  can  be  placed  on  two  8X8  in.  timbers,  as  shown  in 
Fig.  61.  A  discarded  valve  spring,  if  set  under  the  piston 
immediately  below  the  pin,  will  keep  the  pin  raised  from  the 
seats  in  the  bosses  unless  the  pin  is  pressed  downward.  Emery 
paste  is  coated  over  the  two  pin  ends,  and  while  the  pin  is  forced 
into  the  bosses  it  is  rotated  by  a  pin  wrench,  as  outlined 
in  the  sketch.  Removal  of  the  downward  pressure  allows  the 
spring  to  raise  the  pin.  This  action  serves  to  distribute  the 
grinding  paste  over  the  entire  seat,  preventing  the  seat  from 


78 


OIL  ENGINES 


being  ground  hollow.  The  pin  grinding  is  fully  as  important 
as  valve  grinding  although  it  is  done  very  carelessly  in  many 
plants. 

In  reassembling  the  piston,  pin  and  rod  it  is  not  enough  to  sim- 
ply push  the  pin  into  the  bosses  and  tighten  up  on  the  lock-nut. 
The  pin  must  be  driven  in  with  a  sledge  and  copper  mallet  with 
as  great  a  blow  as  an  able-bodied  man  can  deliver.  The  tim- 
orous feeling  many  engineers  have  about  this  driving  process  is 
entirely  without  foundation;  there  is  no  danger  of  fracturing  the 
piston. 


FIG.  61. — Grinding  piston  pin  in  taper  bosses. 

Worn  Piston  Bosses. — On  old  engines  the  bosses  sometimes 
wear  so  oval  as  to  allow  the  pin  to  fit  loosely.  It  is  impossible  to 
secure  a  good  seat  if  this  wear  is  great.  A  partial  remedy  for 
this  condition  is  effected  by  peening  the  bosses  on  the  outside, 
followed  up  by  regrinding. 

Emergency  Piston  Pin. — When  a  pin  has  scored  badly  or 
developed  a  fracture,  it  occasionally  becomes  necessary  to  make 
an  emergency  pin.  Without  question  the  manufacturer  is  the 
proper  party  to  furnish  this  new  part.  But  where  the  engine 
is  urgently  required,  the  engineer  cannot  wait  on  the  slow 
delivery  that  is  so  prevalent.  A  makeshift  pin  can  be  turned 
from  cold  rolled  shafting.  It  should  be  machined  to  size  and 
then  case-hardened  with  bone-black  or  cyanide  of  potassium. 
After  remaining  in  the  fire  for  twelve  hours,  the  pin  should  be 
cooled  off.  As  a  rule,  the  pin  expands  but  slightly  in  the  hard- 
ening process.  The  exact  dimensions  can  be  secured  by  lapping 
with  emery  paste,  although  it  is  a  laborious  procedure. 


CHAPTER  VII 
CYLINDERS  AND  CYLINDER  HEADS 

Since  the  first  Diesel  engines  followed  gas  engine  practice  as 
much  as  was  possible,  it  is  not  surprising  that  the  one-piece 
cylinder  was  incorporated  in  the  first  designs.  At  the  present 
time  no  Diesel  of  any  size  is  fitted  with  a  cylinder  having  the  liner 
cast  integral  with  the  jacket,  though  a  few  small  units  do  use 
it  on  account  of  the  smaller  initial  cost  and  the  consequent  lower 
replacement  expense.  For  cylinders  of  10  inches  or  less  in  bore 
the  one-piece  cylinder  casting  has  no  objectionable  features. 
In  fact,  from  the  operator's  viewpoint  the  one-piece  cylinder  is 
fully  as  serviceable  as  is  the  separate  liner  design.  The  cylinder 
walls  are  always  amply  thick  for  reboring. 

American  Diesel  Engine. — This  pioneer  company  employed 
a  one-piece  cylinder,  as  may  be  seen  in  Fig.  7.  The  bottom  of 
the  liner  is  not  united  with  the  jacket  but  is  free  to  elongate 
without  strain.  This  open  end  of  the  jacket  cavity  is  closed 
with  a  cover  ring.  The  top  is  not  provided  with  cored  water 
passages  to  the  cylinder  head,  the  water  being  passed  into  the 
head  by  outside  gooseneck  connections. 

The  lubrication  of  the  cylinder  is  largely  dependent  on  the 
splashing  of  oil  from  the  enclosed  crank-case.  To  make  the 
oiling  more  certain,  an  oil  line  leads  from  a  mechanical  oil 
pump  to  the  cylinder  about  midway  down  the  cylinder. 

American  Cylinder  Head. — This  head,  a  cross-section  of 
which  appears  in  Figs.  7  and  62,  is  of  irregular  shape,  one  side 
carrying  the  cavity  for  the  air  admission  valve.  The  exhaust- 
valve  cage  is  bolted  to  the  lower  side  of  this  projection.  The 
hot  exhaust  gases  pass  across  the  bridge  or  separator  A,  as  does 
also  the  cold  air  charge.  The  alternate  heating  and  chilling  of 
this  bridge  produce  shrinkage  cracks  that  speedily  extend  en- 
tirely through  the  cast-iron  wall.  This  allows  the  exhaust 
valve  to  leak.  Many  heads  have  been  scrapped  solely  because 
of  this  bridge  fracture.  This  is  totally  an  uncalled-for  extrava- 
gance since  in  all  instances  the  fracture  can  be  repaired  by 
welding. 

79 


80 


OIL  ENGINES 


The  head  is  fitted  with  a  relief  valve.  Unfortunately  few 
operators  test  this  valve;  consequently  it  fails  to  function  when 
an  excessively  high  preignition  pressure  is  experienced  in  the 


FIG.  62. — American  Diesel  cylinder  head. 

cylinder.     The  valve  carbonizes  and  freezes  to  its  seat  unless 
relieved  by  being  lifted  at  least  once  a  week. 

Standard  Fuel  Oil  Engine. — The  cylinder  of  the  engine  manu- 
factured by  the  Standard  Fuel  Oil  Engine  Co.  is  of  one-piece 


E 


FIG.  63. — Longitudinal  section  through  working  cylinder.     Standard  Fuel  Oil 

engine. 

construction,  when  the  power  cylinder  alone  is  considered.  As 
outlined  in  Fig.  63,  the  liner  and  jacket  are  in  one  piece,  the  front 
end  of  which  fits  into  the  frame  casting.  The  scavenging  piston 
works  in  a  bored  cavity  of  the  frame  which  is  not  provided 


CYLINDERS  AND  CYLINDER  HEADS 


81 


with  any  means  of  cooling.  The  power  cylinder,  as  mentioned 
above,  is  fitted  into  this  cavity  and  is  held  by  a  flange.  The  cylin- 
der casting  is  provided  with  ports,  both  for  the  exhaust  gases  and 
for  the  scavenging  air.  The  air  ports,  at  the  top  of  the  cylinder, 
are  arranged  to  give  to  the  air  charge  a  whirling  motion  which 
materially  assists  in  the  scavenging  of  the  exhaust  gases;  see  Fig. 
64.  The  water  spaces  in  the  bridges  are  small  and  tend  to  scale 


Cylinder  Lubricating 
Oil  Passages 


FIG.  64. — Standard  Fuel  Oil  Diesel  section  through  air  and  exhaust  ports. 

if  the  water  is  bad  since  this  is  the  place  of  greatest  temperature. 
If  the  spaces  once  fill  with  scale,  the  bridges  are  subject  to  fracture. 
Periodical  cleaning  of  the  water  jacket  is  imperative. 

Cylinder  Head. — The  cylinder  head,  Fig.  65,  is  water-cooled 
and  contains  but  one  opening — that  for  the  fuel  valve.  Since 
the  water  line  to  the  head  is  separate  from  the  jacket  cooling 
system,  some  engineers  attempt  to  operate  the  engine  on  low 
loads  with  the  head  water  line  cut  .out.  Since  the  head  becomes 
hot,  this  does  improve  the  combustion  on  low  loads.  However, 
there  is  danger  in  the  liability  of  the  head  showing  a  fracture 
on  cooling.  The  joint  between  the  cylinder  and  the  head  should 
be  metal  to  metal.  In  replacing  the  head  the  surfaces  require 


82 


OIL  ENGINES 


a  thorough  cleaning  to  avoid  the  risk  of  small  particles  injuring 
the  gas-tight  joint. 

n 


FIG.  65. — Standard  Fuel  Oil  two  cycle  Diesel  cylinder  head. 

Busch-Sulzer  Diesel  Engine. — This  engine  has  the  liner  cast 
separately  from  the  jacket,  as  appears  in  Fig. 
66.  The  liner  has  a  small  flange  at  the  top, 
which  fits  into  a  recess  machined  in  the  top 
jacket  flange.  The  bottom  is  not  anchored, 
being  free  to  expand  and  contract.  The  head 
has  four  openings,  for  the  exhaust,  admission, 
fuel,  and  air  valves.  The  Busch-Sulzer  Co. 
has  each  cylinder  head  provided  with  a  start- 
ing valve  opening.  This  is  used  with  two 
cylinders  while  on  the  remaining  cylinders  of 
the  engine  the  opening  is  plugged.  Figure  67 
outlines  the  head  of  this  engine,  with  the 
various  openings  as  indicated.  The  same 
general  lines  are  followed  on  practically  all 

FIG.  66. — Busch-Sulzer  other  vertical  engines. 

Diesel  cylinder.          Cylinders  of  A-frame  Engines.— The  Fulton 

Iron  Works,  and  the  Mclntosh  &  Seymour  Co.  in  their  A-frame  en- 


. 


FIG.  67. — Busch-Sulzer  type  B  Diesel  cylinder  head. 

gines,  extend  the  frame  to  act  as  the  cylinder  jacket.     The  liner  in 


CYLINDERS  AND  CYLINDER  HEADS 


83 


many  respects  is  the  same  as  is  found  on  a  box-frame  engine. 
This  frame  and  cylinder  construction  is  very  popular  with 
European  manufacturers  but  is  losing  favor  in  the  United  States. 
It  offers  the  serious  objection  of  high  replacement  cost  in  event 
the  cylinder-jacket  wall  fractures.  This  has  happened  on  a  few 
occasions  in  this  country  and  led  to  its  abandonment  by  at  least 
one  manufacturer.  Figure  68  illustrates  the  Mclntosh  & 
Seymour  A-frame  cylinder.  Their  marine  Diesel  cylinder  appears 
in  Fig.  21. 


FIG.  68. — Mclntosh  &  Seymour  A  frame  Diesel. 

Horizontal  Diesel  Cylinders. — Without  exception  all  manu- 
facturers of  the  horizontal  four-stroke-cycle  engine  extend  the 
frame  casting  to  enclose  the  cylinder  liner,  thereby  forming  the 
water  jacket  without  an  additional  casting. 

Horizontal  Diesel  Cylinder  Heads. — The  manufacturers  of  the 
horizontal  engine  have  two  head  designs  from  which  to  choose. 
If  the  head  be  of  a  symmetrical  design,  such  as  is  found  on  the 
vertical  Diesel  engine,  the  valves  must  be  placed  horizontally. 
Figure  67  shows  a  very  symmetrical  casting  that  is  closely 
followed  on  the  Snow  Oil  Engine  and  on  the  De  La  Vergne  F.D. 
Engine.  This  design  entails  increased  wear  on  the  valve  stems, 
and  the  seating  of  the  valve  is  difficult.  To  obviate  this  condi- 
tion many  manufacturers  have  had  recourse  to  a  head  with 
the  valves  placed  vertically.  This  head,  in  order  to  keep 


84 


OIL  ENGINES 


FIG.    68a. — Mclntosh    &    Seymour 
| A  frame  Diesel. 


FIG.  69. — Cylinder  head  design  with 
vertical  valves. 


FIG.  70. — McEwen  Diesel  cylinder  head. 


CYLINDERS  AND  CYLINDER  HEADS  85 

down  the  compression  volume,  must  be  built  somewhat  along  the 
lines  of  Fig.  69.  It  is  apparent  that  this  form  of  head  will 
experience  certain  casting  strains  which  will  develop  into  frac- 
tures if  they  are  not  removed  by  the  annealing  of  the  entire  head. 
If  this  procedure  is  followed,  no  great  danger  of  fracture  exists. 

McEwen  Diesel  Cylinder  Head. — Figure  70  is  a  view  of  the 
cylinder  head  of  the  McEwen  Diesel. 


FIG.  71. — Allis-Chalmers  Diesel  cylinder. 


Plug  for  Indicator 


Exhaust- 


FIG.  72. — Allis-Chalmers  Diesel  cylinder  head. 

Allis-Chalmers  Diesel  Cylinder. — Figure  71  gives  a  view  of 
the  cylinder  of  this  engine. 

Allis-Chalmers  Cylinder  Head.— The  Allis-Chalmers  Diesel 
employs  the  head  shown  in  Fig.  72.  The  valves  are  set  vertically 
while  the  fuel  nozzle  rests  horizontally  in  the  center  of  the  head 
cover.  65 


86  OIL  ENGINES 

National  Transit  Diesel  Cylinder. — Figure  73  shows  the  cylin- 
der and  head  of  the  first  Diesels  manufactured  by  this  firm. 
Figure  96A  is  a  view  of  the  head  adopted  for  the  1918  Diesels. 
The  valves  are  in  a  horizontal  position  while  the  head  casting  is 
simple,  thereby  removing  practically  all  danger  of  fracture. 


FIG.  73. — National  Transit  Diesel  engine  cylinder  and  cylinder  head. 

Fractured  Cylinders. — The  difficulty  of  fractured  cylinders 
has  been  largely  eliminated  as  a  better  understanding  of  the 
necessity  for  proper  cooling  has  come  to  the  operating  force. 
It  can  be  safely  stated  that  all  cylinder  fractures  are  traceable 
to  improper  cooling.  Many  plants  follow  a  custom  of  cutting  off 
the  flow  of  cooling  water  as  soon  as  the  engine  is  shut  down. 
Since  there  is  about  as  much  heat  absorbed  by  the  water  as  is 
given  up  in  useful  work,  on  shutting  down  a  large  quantity 
of  heat  remains  in  the  iron  parts — this  must  be  taken  up  by 
the  water  contained  in  the  cylinder  jacket.  This  produces  a 
rise  in  temperature  sufficient  to  cause  precipitation  of  the  salts 
suspended  in  the  water.  These  salts  are  deposited  in  the  form 
of  scale  on  the  jacket  walls.  The  action  continues  until  the 
scale  becomes  so  thick  as  to  preclude  the  possibility  of  proper 
cooling.  The  cylinder  walls  attain  a  high  temperature  and 
develop  fractures  because  of  the  inability  of  the  red-hot  walls  to 
withstand  the  high  cylinder  pressure.  Due  attention  to  the 
cooling  water  will  prevent  any  fracture  in  the  cylinder  liner. 

Scored  Cylinders. — In  the  chapter  on  pistons,  several  defects 
that  would  cause  piston  scoring  were  pointed  out,  and  the  discus- 


CYLINDERS  AND  CYLINDER  HEADS  87 

sion  applies  to  cylinders.  Where  the  scoring  is  purely  local  in 
character,  the  surface  can  be  placed  in  working  condition  by 
rubbing  with  an  emery  stone,  finishing  up  with  a  patient  applica- 
tion of  a  scraper.  Ordinarily,  since  the  scoring  is  due  to  piston 
distortion,  the  defective  surfaces  are  not  in  the  plane  of  the  crank 
and  piston;  consequently  the  reduction  of  the  scored  surface 
below  the  cylinder  wall  circle  is  not  of  any  moment.  Another 
type  of  scoring  is  at  times  encountered:  this  has  the  character 
of  grooves  and  ridges.  As  long  as  the  depth  of  the  grooves  is 
.005  inch  or  less  no  serious  damage  will  occur.  But  when  second- 
ary ridges  appear  between  the  original  ridges,  the  liner  must  be 
rebored. 

Reboring  Cylinders. — The  natural  course  of  wear  in  the  liner 
increases  the  clearances  to  such  an  extent  as  to  require  reboring. 
The  liner,  as  an  average,  will  need  replacement  or  reboring  every 
three  to  five  years,  dependent  on  the  hours  of  service  and  the 
attention  it  has  received. 

When  the  engineer  is  confronted  with  the  problem  of  cylinder 
reboring,  it  is  well  for  him  to  shift  the  work  to  the  shoulders  of 
some  machine  shop  that  makes  a  specialty  of  such  work.  The 
actual  reboring  is  not  hard,  neither  is  the  setting  up  of  the  boring 
machine;  however,  it  requires  a  boring  bar  that  will  cost  around 
$800,  and  few  shops  are  willing  to  place  their  machine  on  a  rental 
basis.  A  shop  that  does  much  of  this  work  charges  $15  per  inch 
of  cylinder  diameter — a  16X24  in.  cylinder  would  cost  $240 
to  be  rebored  and  fitted  with  a  new  piston.  This  represents  a 
fair  charge  and  is  far  less  costly  than  the  entire  replacement  of 
the  liner. 

Liner  Replacement. — All  cylinders  are  of  a  thickness  that  will 
allow  at  least  one  reboring.  If  the  liner  becomes  worn,  after  it 
has  had  one  reboring,  or  if  it  is  fractured,  the  withdrawal  of  the 
damaged  liner  is  easily  effected  by  the  use  of  the  draw-bolt,  as 
outlined  in  Fig.  74.  The  spider  may  be  made  with  either  two 
or  three  fingers;  the  two  fingers  are  as  serviceable  as  the  three 
fingers.  The  bolt  is  of  l%g-inch  cold  rolled  shafting,  the  thread 
having  a.lj^-inch  diameter.  The  spiders  are  placed  over  the 
cylinder  flange  and  the  front  end  of  the  liner  as  indicated.  A 
part  turn  of  the  nut  will  bring  the  rod  under  tension;  a  few  sharp 
blows  on  the  inner  surface  of  the  liner  at  the  head  end  will,  in 
most  cases,  loosen  it  so  that  the  bolt  can  pull  it  out  with  ease.  If 


88 


OIL  ENGINES 


the  liner  resists,  additional  bolt  tension,  followed  with  hammer 
blows  along  the  liner  supports,  will  expedite  the  removal. 

In  inserting  a  new  liner  the  oil  passages  must  check,  as  also 
must  the  dowels.  After  the  casting  has  been  driven  into  place 
by  the  use  of  a  sledge  and  hardwood  block,  the  bolt  and  spiders 
used  in  removing  the  discarded  part  can  be  reversed  to  press  the 
liner  into  the  recess. 


[S* Threaded  IJ*1 


L, 

I 

a 

i: 

] 

y 

^g 
J 

(        in" 

J 

c 

1 


Top  Plate 


Bottom  Plat* 

Fio.  74. — Removing  cylinder  liner  screw  jack. 

Cylinder  and  Head  Joints. — While  a  few  engineers  depend  on 
a  metal-to-metal  joint  at  the  head  to  withstand  the  cylinder 
pressures,  some  form  of  gasketing  is  now  well-nigh  universal. 
The  gasket  may  be  either  a  flat  copper  ring,  a  copper  wire,  or  a 
round  rubber  ring. 

The  flat  copper  ring  is  very  successful  as  a  gas  check  and  is 
not  difficult  to  make.  Its  objectionable  feature  is  the  large 
amount  of  sheet  copper  that  is  wasted  in  cutting  the  ring.  Ex- 


CYLINDERS  AND  CYLINDER  HEADS 


89 


perience  proves  that  the  thinner  copper  sheet  makes  the  best 
gaskets;  ^2~incn  thickness  of  metal  is  ample  and  enables  the 
gasket  to  conform  to  the  flange  face.  The  gasket  is  best  cut 
scant  so  that  it  fits  easily  into  the  gasket  recess.  If  it  is  so  wide 
as  to  require  driving,  the  edges  will  bend  and  the  gasket  will  not 
prove  gas-tight.  If  a  gasket  cutter  is  not  at  hand,  a  pair  of  tin- 
ner's shears  will  be  very  satisfactory.  A  wooden  mallet  is  handy 
to  hammer  the  gasket  to  a  flat  surface. 

In  case  sheet  copper  cannot  be  procured,  an  equally  service- 
able ring  can  be  made  of  No.  10  gage  soft  copper  wire;  when  the 
bare  copper  is  not  available,  water-proofed  electrical  wire  of 
No.  10  gage  may  have  its  insulation  burned  off  and  the  bare  wire 
used.  The  wire  is  formed 
into  a  circle  of  the  proper 
diameter  and  the  ends  sol- 
dered together.  If  the  cyl- 
inder flange  is  not  provided 
with  a  recess  to  receive  the 
ring,  the  latter  should  be 
placed  inside  the  bolt  circle, 
touching  each  stud.  This 
allows  the  leverage  to  be  a 
minimum.  The  wire  must  be 
free  from  kinks  or  bends. 

Round  rubber  gaskets  are 
often  used  on  vertical  engines, 
particularly  on  the  Mclntosh 
&  Seymour  engines.  The  rubber  tubing  is  shaped  into  a  ring 
of  the  proper  diameter  and  the  ends  united  by  rubber  glue.  In 
engines  where  the  cooling  compartment  of  the  head  communicates 
with  the  cylinder  jacket  by  cored  openings  at  the  flange  the 
openings  are  surrounded  with  like  tubes.  These  gaskets  of 
rubber  tubing  can  always  be  obtained  from  the  engine  builder, 
but  any  mill  supply  house  will  furnish  the  tubing  in  coils  at  a 
far  less  cost. 

Drawing  Up  Cylinder  Stud  Nuts. — In  tightening  up  the  cyl- 
inder-head nuts,  many  engineers  draw  up  one  nut  as  snugly  as 
possible  before  drawing  up  any  of  the  other  nuts.  Such  handi- 
work is  evidence  of  a  lack  of  mechanical  knowledge  and  is  to 
be  shunned.  If  the  top  of  the  studs  are  numbered  in  pairs, 
similar  to  Fig.  75,  and  tightened  in  rotation,  the  head  can  be 


FIG.  75. — Method  of  drawing  up 
head  nuts. 


00  OIL  ENGINES 

drawn  down  quite  evenly.  As  example,  all  the  nuts  are  run 
down  against  the  head,  then  the  No.  1  nuts  are  given  an  eighth 
turn,  followed  by  a  similar  performance  on  No.  2  nuts,  etc.  Re- 
turning to  the  No.  1  nuts,  they  are  given  another  eighth  turn, 
etc.  When  giving  the  nuts  the  final  movement,  a  workman  can 
strike  the  wrench  handle  several  sharp  blows  with  a  sledge. 

Fractured  Heads. — Fracture  of  a  cylinder  head  is  a  malady 
which  appears  to  afflict  all  makes  of  Diesels,  no  matter  what 
the  design  may  be.  There  is  no  doubt  that  the  more  complicated 
heads  fracture  often,  but  even  the  simplest  of  head  castings  do 
give  .way,  usually  on  heavier  loads.  Bad  water,  without  ques- 
tion, occasions  the  greater  number  of  the  fractured  cylinder 
heads.  This  especially  applies  to  the  horizontal  engine.  Here, 
on  shutting  down,  the  water  gives  up  its  salts,  which  deposit 
on  the  iron  surfaces.  The  greater  part  settles  on  the  lower 
surfaces,  marked  A  in  Fig.  69.  However,  a  part  of  the  soft 
sludge  adheres  to  the  vertical  surfaces  B.  This  coating  accu- 
mulates until  it  is  as  much  as  an  inch  thick.  Since  scale  is  an 
excellent  non-conductor,  no  cooling  effect  is  experienced  on  the 
hot  cast-iron  head  wall  which  i's  in  contact  with  the  intense 
flame  of  the  burning  fuel.  On  cooling,  the  contraction  of  the 
iron  gradually  weakens  the  bond  of  the  scale.  This  scale  ulti- 
mately drops  off  while  the  engine  is  under  load,  exposing  a  red- 
hot  iron  surface  to  the  cooling  water.  The  sudden  localized 
contraction  of  the  iron  on  being  chilled  results  in  a  fractured 
head.  Evidently  the  horizontal  head  is  more  likely  to  shed 
the  scale  than  is  the  vertical  head.  It  becomes  necessary  for 
an  engineer  to  inspect  the  cylinder  head  at  stated  intervals;  if 
scale  is  present,  it  can  be  removed  by  scraping.  If  a  solution 
of  muriatic  acid  and  water  in  the  proportion  of  one  to  ten  is 
allowed  to  remain  in  the  jacket  a  few  hours,  all  the  scale  can  be 
washed  out  with  a  hose. 

Heat  stresses  due  to  faulty  design  of  the  head  also  contribute 
to  these  fractures.  This,  however,  is  beyond  the  sphere  of  the 
operating  force,  although  every  engineer  should  endeavor  to 
persuade  the  management,  when  new  units  are  to  be  installed, 
to  purchase  only  those  engines  whose  design  offers  comparative 
freedom  from  operating  difficulties. 

Cylinder  heads  frequently  crack  through  the  bridge  between 
the  exhaust  and  fuel  valve  cavities.  These  fractures  are  due 
to  improper  cooling  rather  than  to  faulty  design,  although  there 


CYLINDERS  AND  CYLINDER  HEADS  91 

are  doubtless  instances  where  casting  fractures  develop  at 
these  places  as  soon  as  the  head  is  machined.  To  safeguard 
the  engine  head  from  such  fractures  that  may  develop  in  service, 
the  flow  of  cooling  water  to  the  head  must  be  positive  and  the 
temperature  kept  at  a  constant  reading,  the  value  of  which  can 
only  be  determined  by  experiment  on  the  particular  engine. 

On  marine  Diesels  the  fracturing  of  cylinder  heads  is  directly 
traceable  to  excessive  overloads.  In  a  heavy  sea  the  propellor 
is  at  times  exposed  and  immediately  thereafter  completely 
buried.  This  leads  to  engine  hunting,  and  neither  governor  nor 
manual  control  can  cope  with  the  situation.  The  fuel  pumps 
deliver  excessive  charges  to  the  cylinder,  creating  pressures 
beyond  the  capacity  of  the  heads  to  withstand. 

Furthermore  the  marine  engine,  to  reduce  the  weight  per 
horsepower,  is  speeded  far  higher  than  the  stationary  Diesel. 
This  applies  especially  to  the  submarine  and  light  cruising 
engines.  The  heat  absorbed  per  sq.  inch  of  surface  by  the 
heads  of  a  500  h.p.  engine  at  400  r.p.m.  is  double  the  amount 
absorbed  by  the  heads  of  a  500  h.p.  at  200  r.p.m.,  since  the 
cylinder  bore  is  practically  one-half  that  of  the  latter  engine 
and  the  total  amount  of  heat  absorbed  is  approximately  the 
same.  The  cooling  system,  then,  must  be  absolutely  correct 
in  design  if  fractures  are  to  be  avoided.  The  tendency  of  the 
salt  water  to  scale  is,  of  course,  more  pronounced  where  the 
temperatures  are  as  high  as  exist  in  the  marine  Diesel  heads. 

Repair  of  Fractured  Cylinder  Heads. — Oxyacetylene  welding 
has  not  been  a  marked  success  in  the  repairing  of  cracked  cylinder 
heads.  The  cylinder  head  contains  a  great  weight  of  iron,  and, 
in  welding,  the  flame  is  localized.  The  consequence  is  that  the 
metal  immediately  about  the  fracture  is  highly  heated  and  ex- 
pands. After  the  molten  metal  is  added,  closing  the  fracture, 
the  head  is  allowed  to  cool.  The  mass  of  the  head  has  not 
been  heated,  and  so  shows  no  contraction.  The  obvious  result 
is  the  shrinkage  of  the  metal  at  the  edges  of  the  fracture, 
reestablishing  the  fault. 

To  successfully  weld  a  cylinder  head,  a  furnace  similar  to 
Fig.  76  can  be  constructed  of  fire  brick.  The  floor  should  also 
be  made  of  fire  brick  supported  by  old  grate  bars  or  iron  rods. 
After  a  coke  fire  has  been  burning  about  the  head  for  twenty- 
four  hours,  the  entire  casting  becomes  red-hot.  The  oxy- 
acetylene  flame  is  then  applied;  the  fracture  is  enlarged  to  a 


92 


OIL  ENGINES 


trough  shape,  thus  allowing  the  added  metal  to  reach  the  bottom 
of  the  fracture.  The  new  metal  is  deposited  in  small  quantities 
and  thoroughly  welded  to  the  cast  iron  before  more  is  added. 
The  head  should  then  be  left  in  the  furnace  to  cool  for  forty- 
eight  hours.  Since  the  entire  furnace  has  been  at  a  high  tem- 


FIG.  76. — Repair  of  fractured  cylinder  head. 

perature,  the  cooling  will  be  very  gradual,  thereby  avoiding  all 
shrinkage  strains.  If  the  fracture  has  been  across  a  valve  seat, 
the  part  must  be  machined  and  the  valve  refitted.  The  proc- 
ess of  welding  here  outlined  has  been  followed  with  complete 
success,  saving  hundreds  of  dollars  in  a  plant  where  five  Diesels 
were  installed. 


CHAPTER  VIII 
ADMISSION  AND  EXHAUST  VALVES 


TYPES.    ADJUSTMENTS.     REPAIRS 

Valves. — The  four-stroke-cycle  Diesel  engines  are  provided 
with  air  admission  and  exhaust  valves  as  are  all  four-stroke- 
cycle  gas  engines.  In  fact,  a  number  of  Diesels  are  built  with 
cylinder  heads  and  valve  mechanisms  that  are  but  slight  devia- 


FIQ.  77. — Admission  valve  cage.     American  Diesel. 

tions  from  the  similar  parts  of  a  gas  engine.  This  applies  par- 
ticularly to  the  horizontal  Diesel  of  which  a  number  possess 
what  might  well  be  termed  "gas  engine  heads."  In  the  vertical 
engines  the  entire  valve  equipment  is  distinctly  a  Diesel  feature, 
differing  in  many  respects  from  any  of  the  gas  engine  designs. 

In  all  Diesels  the  admission  valves  seat  in  valve  cages  along 
the  lines  of  Fig.  77;  the  builders  are  not  so  unanimous  as  to  the 
exhaust  valve.  This  latter  valve,  in  some  engines,  is  provided 

93 


94  OIL  ENGINES 

with  a  cage;  in  other  makes  the  valve  seats  directly  on  the 
cylinder  casting;  in  others  a  removable  seat  which  is  fastened 
to  the  head  casting  is  supplied.  Strictly  speaking,  the  exhaust 
rather  than  the  admission  valve  should  be  fitted  into  a  cage. 
The  hot  exhaust  gases,  in  passing  through  the  valve  opening, 
wear  the  ground  seats  very  rapidly,  while  the  admission  valve 
is  not  subject  to  such  an  erosive  action.  From  the  operator's 
viewpoint  the  exhaust  valve  should  be  caged,  as  well  as  the 
admission  valve.  Engine  builders,  in  a  desire  to  eliminate  the 
difficulty  of  lowering  the  exhaust  cage  under  the  cylinder  head, 
place  the  admission  valve  in  a  cage  and  design  the  exhaust  valve 
with  a  diameter  to  allow  the  latter  to  be  lifted  up  through  the 
admission  valve  cavity  after  the  admission  valve  assembly 
has  been  removed.  This  enables  the  engineer  to  grind  the 
exhaust  valve  by  inserting  the  pin  wrench  through  the  admission 
opening. 

In  the  horizontal  engines  where  the  valves  are  placed  with  the 
stems  in  a  horizontal  position,  as  well  as  in  the  vertical  engines, 
usually  both  valves  are  caged. 

Valve  Camshafts  and  Levers. — The  present-day  vertical  Die- 
sels of  American  manufacture  have  camshafts  along  the  cylinder 
heads  and  are  driven  by  a  vertical  shaft  from  off  the  crank- 
shaft. The  drive  is  invariably  by  helical  gearing.  The  cam- 
shaft carries  the  cams  for  the  admission,  exhaust,  injection  and 
starting  valves;  the  cams  are  usually  of  cast  steel,  with  a  tool- 
steel  nose  on  the  fuel-injection  cam.  The  lever  mechanisms  are 
quite  similar  for  all  makes  of  vertical  engines,  the  variation 
being  mainly  in  the  arrangement  for  operating  the  starting  valve. 

The  horizontal  engines  are  all  fitted  with  a  layshaft  along 
the  engine  frame  which  is  driven  on  a  2  to  1  ratio  from  the  main 
shaft.  The  valves  receive  their  motion  from  cams  or  eccentrics 
mounted  on  the  layshaft. 

American  Diesel  or  Busch-Sulzer  Type  A. — The  former  engine, 
which  was  the  forerunner  of  the  Busch  Type  A  engine,  is  of 
interest  since  many  are  still  in  operation.  The  positions  of  the 
admission  and  exhaust  valves  are  shown  in  Fig.  7.  The  cam- 
shaft is  mounted  within  the  enclosed  crank- case  and  is  driven 
from  the  main  shaft,  through  an  idle  or  intermediate  gear,  and 
operates  at  half  engine  speed.  The  exhaust  valve  seats  vertically 
in  the  lower  face  of  the  head  and  is  driven  directly  by  a  ver- 
tical push-rod  pinned  to  the  valve  lever  B.  The  lever  is  closed 


ADMISSION  AND  EXHAUST  VALVES 


95 


by  a  spring  which  is  held  in  place  by  a  washer  and  lock-nuts 
as  shown  in  Fig.  78.  This  valve  has  two  tapped  holes  in  the 
top  which  allow  a  wrench  to  be  used,  but  the  size  of  the  cap 
screws  are  such  that  it  is  impossible  to  hold  the  valve  with 
the  wrench  when  disassembling.  The  most  satisfactory  pro- 
cedure to  follow  is  outlined  in  the  sketch  to  the  left  of  Fig.  78. 
The  spring  is  compressed  by  a  pinch-bar,  allowing  the  engineer 
to  grasp  the  valve  stem  with  a  pipe  wrench.  By  placing  an 


Copper  Gasket 


Wrench 


.-•Clearance  ft" 
Valve  Push  Rod 

FIG.  78. — American  Diesel  exhaust  valve. 

open-end  wrench  on  the  lock-nuts  the  nuts  can  be  removed, 
whereupon  the  spring  is  released  and  the  valve  withdrawn. 
The  valve  has  a  45-degree  angle  to  its  face,  seating  directly  on 
the  cast-iron  base  of  the  cylinder  head.  If  the  engineer  desires 
to  regrind,  the  valve  is  reinserted  on  the  stem  housing  and  a 
light  spring  set  below  the  valve  as  indicated  by  the  dotted 
outline. 

The  valve  stem  housing  is  not  bushed  and  in  time  wears 
enought  to  emit  part  of  the  exhaust  gases.  This  can  be  elimi- 
nated by  the  reaming  of  the  housing  and  the  insertion  of  a  brass 
tube  of  the  correct  diameter  and  bore.  The  exhaust  pot  has  a 


96  OIL  ENGINES 

water  drip  connection  for  the  purpose  of  maintaining  the  tem- 
perature at  a  reasonably  low  value.  A  drip  cock  is  also  a 
useful  adjunct  to  the  pot  since  it  will  free  the  chamber  of  tarry 
deposits.  The  junction  of  the  pot  and  cylinder  head  is  sealed 
by  a  copper  gasket.  It  is  absolutely  necessary  that  the  stud- 
bolts  have  clean  threads  for  they  are  rather  inaccessible,  and 
if  the  stud  nuts  are  not  tight  the  gasket  will  blow. 

Admission  Valve. — The  admission  valve  is  contained  in  a  cage, 
Fig.  77,  and  is  actuated  by  a  cam,  similar  to  the  exhaust  cam, 
through  the  lever  and  push-rod  shown.  The  cage  has  a  gasketed 
joint  at  a.  In  placing  the  copper  gasket  on  the  joint  and  setting 
the  valve  cage  into  position,  care  is  to  be  exercised  to  prevent 
the  gasket  from  wedging. 

Adjustments. — The  valve  lever,  since  the  clearance  between  its 
end  and  the  valve  nut  is  large,  delivers  a  hammer  blow  to  this 
nut  and  the  fibre  washer.  The  washer  wears  rapidly  while  the 
nut  gradually  shears  the  threads  on  the  valve  stem.  The  valve 
stem  can  be  turned  down  apd  threaded  to  take  a  smaller  diameter 
nut;  a  second  remedy  is  tlje  employment  of  a  cotter  pin  through 
the  worn  nut  and  valve  stem:f  The  bushings  on  the  lever  pins 
also  wear  rapidly;  these  cari  be  replaced  by  new  bushings. 
The  pins  frequently  become  flat,  and  new  pins  of  machine 
steel,  case-hardened,  can  be  turned  to  replace  the  defective  ones. 
If  the  pins  are  oiled,  as  they  should  be,  little  wear  will  occur;  while 
the  pin  bearings  have  only  oil  holes,  small  oil  cups  are  far  more 
serviceable. 

In  regrinding  this  valve  the  unit  is  disassembled.  The  valve 
is  reinserted  in  the  cage  and  the  dashpot  again  placed  on  the 
valve  stem.  This  constrains  the  valve  stem  to  remain  in  its 
proper  position  while  the  valve  face  is  ground  to  the  correct 
angle. 

Adjusting  Valve  Levers. — The  long  nut  on  the  upper  end  of 
the  exhaust  valve  push-rod  is  screwed  on  until  it  clears  the  valve 
stem  nuts  by  J-f  6  inch  when  the  valve  is  at  rest  and  the  push-rod 
is  in  its  lowest  position.  The  lock-twits  on  both  push-rod  and 
valve  stem  must  be  jammed  tight  to  prevent  any  change  in  this 
clearance  when  the  engine  is  running.  The  upper  end  of  the 
admission  valve  push-rod  is  adjusted  to  allow  the  valve  end  of 
the  rocker  to  clear  the  fibre  washer  by  3^2  mcn  when  the  valve 
is  seated. 

A  layout  of  the  valve  mechanism  is.  shown  in  Fig.  7.     This 


ADMISSION  AND  EXHAUST  VALVES 


97 


also  includes  the  fuel  valve  rocker  arm  and  rod.  The  cams  are 
of  cast  steel  keyed  to  the  camshaft.  Change  in  the  timing  of  the 
cam  assembly  can  be  effected  by  shifting  the  cam  gear  a  tooth 
or  two.  This  is  made  possible  by  sliding  the  idle  gear  until  it 
is  out  of  mesh  with  the  cam  gear.  Alteration  of  an  individual 
cam  is  obtained  by  the  employment  of  an  offset  key  which  will 
ove  the  cam  the  required  amount. 


I     J 

FIG.  79. — Valve  timing  of  American  Diesel  engines. 

Valve  Timing. — Figure  79  gives  the  timing  of  admission, 
exhaust  and  fuel  valves  on  the  225  h.p.  American-Diesel  engine. 
These  timings  represent  standard  practices  and  are  equally 
applicable  to  120  and  170  h.p.  engines  of  this  make.  In  this 
diagram  each  quarter  circle  represents  180  degrees  and  not  90 
degrees,  being  equal  to  one  complete  stroke  of  the  engine 
piston.  The  degrees  indicated  are  to  be  laid  off  on  the  fly- 
wheel rim  and  are  not  percentages  of  the  piston  travel.  To 
translate  these  degrees  to  inches  on  the  periphery  of  the  flywheel 
is  a  matter  of  simple  mathematics.  For  example,  if  the  wheel 
be  8  feet  in  diameter,  .the  circumference  is  then  302  inches. 


98 


OIL  ENGINES 


One  degree  is  in  this  case  30%60  ~  mcn  or  -83  +  inch.  If 
the  operator  uses  a  value  of  .8  inch  per  degree,  he  will  be  working 
amply  close. 

Busch-Sulzer  Type  B  Diesel  Valves. — In  exterior  form  the 
admission  and  exhaust  valves  and  cages  are  quite  similar. 
Both  are  placed  vertical  in  the  cylinder.  The  interior  arrange- 
ment of  the  cages,  however,  are  by  no  means  identical.  The 
exhaust  valve  cage  has  a  removable  valve  stem  bushing;  the 
cavity  between  this  bushing  and  the  cage  body  constitutes 
the  cooling  water  jacket.  The  admission  valve  cage  has  the 
valve  stem  support  cast  integral  with  the  cage  proper.  Both 


FIG.  80. — Busch-Sulzer  type  B  Diesel  exhaust  valve  and  rocker. 


cages  are  provided  with  removable  seats  as  appears  in  Fig.  80. 
This  feature  is  of  importance  to  the  operator  since  it  obviates 
the  necessity  of  replacement  of  the  complete  cage  when  the 
valve  seat  has  been  worn  excessively. 

The  valves,  both  admission  and  exhaust,  have  cast-iron  bodies 
with  steel  stems.  In  disassembling  the  valve,  the  lock-nuts 
D  and  E  are  unscrewed,  the  valve  being  held  by  a  pin  wrench 
inserted  in  the  two  pin  holes  in  the  valve  body.  The  removal 
of  the  spring  cap  F  allows  the  valve  to  be  withdrawn.  The 
exhaust  valve  seat,  of  course,  experiences  the  greatest  wear ; 
consequently  frequent  refacing  of  the  cage  seat  becomes  neces- 
sary. After  a  number  of  refacings  with  a  reamer  the  cage  seat 
lies  too  deep  in  the  cage;  when  this  occurs,  a  new  removable 
seat  ring  can  be  obtained. 


ADMISSION  AND  EXHAUST  VALVES 


99 


Cam  Levers.  —  The  valves  are  actuated  by  levers  which 
receive  their  motion  from  a  camshaft  that  lies  along  the  cylinder 
head.  This  camshaft  is  driven  by  the  engine  shaft  through  the 
intermediation  of  the  vertical  governor  shaft  and  two  sets  of 
helical  gears. 

To  allow  the  valves  and  cages  to  be  lifted  without  the  re- 
moval of  the  entire  rocker  arm  and  shaft,  the  rockers  are  in 
two  parts.  These  two  parts  are  held  together  by  one  bolt  A 
while  two  dowel  pins  B  preclude  the  possibility  of  the  parts 


FIG.  81.— Busch-Sulzer  500  H.P.  type  B  4  cylinder,  200  R.P.M.  Diesel  valve 

timing  diagram. 

being  improperly  aligned  on  reassembly.  One  end  of  the  rocker 
carries  a  hardened  steel  roller  while  the  other  end  is  fitted  with 
the  adjusting  screw  G,  which  screws  into  a  steel  pin  and  is 
locked  by  the  nut  H. 

Valve  Lever  Clearances. — The  adjusting  screw  enables  the 
operator  to^obtain  the  required  clearance  between  the  roller 
and  the  cam  when  the  valve  is  closed.  The  rocker  arm  is  held 
against  the  valve  stem,  and  the  clearance  is  measured  between 


100 


OIL  ENGINES 


roller  and  cam  by  ordinary  thickness  gages.  The  clearance 
values  that  are  correct  for  all  sizes  of  the  Busch-Sulzer  Type 
B  engines  are  as  follows: 

Admission  valve  cam  clearance 0 . 012  inch 

Exhaust  valve  cam  clearance 0 . 018  inch 

Fuel  valve  cam  clearance 0 . 004  inch 

Starting  valve  cam  clearance 0. 012  inch 

Since  the  clearances  are  established  when  the  engine  is  cold, 
it  becomes  necessary  to  note  whether  the  valves  close  after  the 
engine    has    become    warmed. 
If  not,  the  adjusting  or  push  . 
screws   can  be   backed  off  to 
give  these  values.      Figure  81 
is  the  usual  valve  timing  on 
this  engine. 

Camshaft     Layout. — Figure 
82  is  a  schematic  outline  of  the 


FIG.    82. — Busch-Sulzer  Diesel  rocker  FIG.  83. — Lever  shaft, 

layout. 

actuating  valve  levers  of  the  Busch-Sulzer  engine.  The  lever 
shaft  g  is  supported  by  the  pedestal  bearings,  better  shown 
in  Fig.  83.  The  lever  d  controls  the  exhaust  valve,  while  a 
actuates  the  air  admission  valve,  and  the  lever  b  governs  the 
fuel  valve,  the  lever  c  opening  the  air  starting  valve  in  starting 
the  engine.  The  levers  b  and  c  are  mounted  on  an  eccentric 
bushing  which  is  supported  by  the  shaft  g.  In  starting,  the  lever 
o  moves  the  eccentric  bushing  to  the  " starting"  position  where 
the  fuel  lever  b  does  not  engage  its  cam  6;  this  movement  brings 
the  starting  lever  c  into  contact  with  its  cam  c.  This  action  is 


ADMISSION  AND  EXHAU&T  V 


t'Ol 


carried  out  on  the  two  starting  cylinders;  on  the  two  idle  cylin- 
ders the  eccentric  handle  is  moved  to  the  neutral  position, 
cutting  out  the  fuel  valve.  It  should  be  understood  that  only 
the  two  starting  cylinders  have  the  starting  valves.  Figure  83 
also  shows  the  cam  arrangement. 

Mclntosh  &  Seymour  Diesel  Valves. — The  admission  and 
exhaust  valves  of  this  engine  follow  the  form  shown  in  Fig.  84. 
Both  valves  have  the  same  dimensions,  the  difference  between  the 
two  being  the  removable  seat  used  on  the  exhaust  valve;  the 
valve  seats  have  a  60-degree  angle  with  the  stem.  This  seat  is 


FIG.    84. — Mclntosh    &    Seymour    Diesel 
exhaust  valve. 


FIG.  85. — Exhaust    valve   and 
cage. 


an  alloy-steel  ring  held  in  place  by  two  countersunk  screws.  In 
renewing  this  ring  it  is  very  essential  that  the  surfaces  be  thor- 
oughly cleaned.  Occasionally  the  ring  is  slightly  distorted 
when  received;  it  must  be  ground  true  before  it  is  placed  on  the 
valve.  The  exhaust  and  admission  valve  cages  are  of  the  same 
external  dimensions.  They  differ  only  in  the  exhaust  cage 
having  a  water  cavity  around  the  valve  stem.  The  cages  rest 
in  machined  cavities  in  the  head,  the  joint  at  the  point  a  being 
sealed  with  a  copper  gasket.  The  gasket  must  be  of  the  proper 
width  to  eliminate  danger  of  cramping  when  the  cap  is  placed 
over  it.  Figure  85  shows  the  exhaust  valve  and  its  cage. 


102 


6ft  ENGINES 


To  disassemble  the  valve,  the  pin  b,  Fig.  86,  is  driven  out  of 
the  valve  stem,  and  the  bushing  a  is  removed.  The  spring  cap 
d  is  pushed  downward,  allowing  the  slotted  ring  c  to  be  slipped 
from  around  the  valve  stem.  This  being  done,  the  spring  cap 
and  the  spring  are  withdrawn  from  the  top  of  the  cage  while  the 
valve  can  be  removed  through  the  bottom  end  of  the  cage. 


B  Pin  through  Valve 
Stem  and  Bushing  A 


FIG.  86. — Mclntosh  and  Seymour  valve  layout. 

Camshaft. — The  camshaft  lies  along  the  cylinder  heads,  rest- 
ing in  bearing  pedestals  mounted  on  extensions  from  the  cylinder 
castings.  The  camshaft  is  driven,  through  helical  gears  and  a 
vertical  governor  shaft,  by  the  main  engine  shaft. 


FIG.  87. — Mclntosh  &  Seymour  valve  rocker  layout. 

Figure  87  shows  the  valve  rocker  arrangement  where  d  is  the 
exhaust  rocker,  a  is  the  admission  rocker,  b  the  fuel  rocker,  and 
c  the  air  starting  rocker.  The  cams  for  b  and  c  are  in  one  piece ; 
the  engine  is  started  by  shifting  the  starting  roller  c  until  it  con- 
tacts with  the  starting  cam ;  a  small  lever  is  provided  on  the  rocker 
for  this  purpose.  After  the  engine  fires,  the  roller  c  is  moved  out 
of  contact  with  its  cam. 


ADMISSION  AND  EXHAUST  VALVES 


103 


In  removing  the  valve  cages,  the  caps  of  the  pedestal  bearings 
/,  Fig.  86,  are  first  unbolted  and  a  rope  sling  passed  around  the 
ends  of  this  rocker  shaft.  Since  the  shaft  is  lifted,  the  entire 
valve  rocker  mechanism  for  this  particular  cylinder  is  removed. 
While  this  appears  to  be  a  more  difficult  task  than  the  removal 
of  part  of  a  rocker  arm  as  in  Fig.  80,  actually  it  consumes  no 
more  time  and,  if  the  plant  possesses  a  traveling  crane  hoist,  is 
no  more  difficult. 


FIG.  88.  —  Valve  timing  Mclntosh  &  Seymour  500  H.P.  Diesel  engine  164  R.P.M. 
4  cylinders  18%  dia.  X  28%  stroke. 


Valve  Cam  Clearances.  —  The  roller  clearances  to  be  main- 
tained are  as  follows: 

Admission  valve  cam  clearance  ................  0  .  039  inch 

Exhaust  valve  cam  clearance  ..................  0  .  036  inch 

Fuel  valve  cam  clearance  .....................  0  .  002  inch 

Starting  valve  cam  clearance  ..................  0  .  036  inch 

Figure  88  gives  the  valve  timing  which  is  correct  for  the 
500  h.p.  engine  at  164  r.p.m.,  and  this  equally  applies  to  all 
sizes  of  the  slow-speed  engine.  The  manufacturers  set  the 
admission  and  exhaust  valves  on  the  erecting  floor  and  do  not 


104 


OIL  ENGINES 


recommend  any  change.  The  helical  gears  are  marked  to  enable 
the  erector  to  assemble  the  valve  mechanism.  Nevertheless, 
after  a  few  years  of  service  the  gear  teeth  and  the  cams  wear 
to  such  an  extent  that  the  valves  do  not  function  as  originally 


FIG.  89. — Snow  Diesel  admission  valve. 


set.     It  then  becomes  necessary  to  retime  the  valves  along  the 
settings  indicated  above. 

The  rocker  shaft  is  provided  with  small  grease  cups.  Usually 
the  lubrication  so  obtained  is  insufficient,  and  the  cups  should 
be  replaced  by  sight-feed  oil  cups. 


ADMISSION  AND  EXHAUST  VALVES 


105 


Snow  Diesel  Engine  Valves.—  Figure  89  outlines  the  admission 
valve  while  Fig.  90  is  the  exhaust  valve  assembly  of  the  Snow 
engine.  The  valve  stems  are  identical,  while  the  valve  bodies 
differ  in  that  the  exhaust  valve  body  is  extended  along  the  stem, 


FIG.  90. — Snow  Diesel  exhaust  valve. 


forming  a  gas  deflector  to  avoid  the  burning  of  the  stem.  The 
valves  have  one  feature  that  makes  them  rather  peculiar — the 
valve  seats  are  flat  surfaces.  The  advantage  of  the  flat  valve 
lies  in  its  freedom  from  any  wedging  action,  with  the  consequent 
grooving  which,  at  times,  occurs  with  the  bevel  seat,,  and  in  the 


106 


OIL  ENGINES 


increased  valve  opening  over  the  bevel  seated  valve  for  any 
given  lift.  There  is,  however,  an  objection  to  the  flat  valve 
which  an  occasional  engineer  voices.  It  is  much  more  difficult 
to  keep  gas-tight,  largely  due  to  the  accumulation  of  small  carbon 
particles  on  the  face.  The  valves  are  easier  to  regrind,  and  con- 
sequently any  deposits  can  be  quickly  removed. 

The  valve  stem  is  equipped  with  labyrinth  grooves,  and  it 
becomes  necessary  to  clean  these  recesses  of  tar  each  time  the 
valve  is  inspected.  Since  the  side  pressure  from  the  rocker  arm 


FIG.  91. — Snow  Diesel  camshaft  and  valve  rockers. 


is  against  the  stem,  the  stem  must  be  copiously  lubricated;  this 
is  obtained  by  a  line  from  the  mechanical  oil  pump  on  the  engine 
frame.  The  cage  is  sealed  by  a  ground  joint  at  the  inner  end 
as  well  as  by  a  gasket  at  the  outside  flange. 

Camshaft. — The  camshaft,  as  will  be  noted  in  Fig.  91,  is 
driven  by  bevel  gears  from  the  engine  lay  shaft.  The  rockers 
are  fulcrumed  on  a  short  shaft  which  is  supported  by  the  cylinder 
head.  To  remove  a  valve  cage,  the  entire  rocker  assembly  must 
be  unbolted.  This  fulcrum  shaft  is  provided  with  an  eccentric 
bushing  upon  which  are  fitted  the  starting  and  fuel  valve  rockers. 


ADMISSION  AND  EXHAUST  VALVES  107 

Cam  Clearances. — The  proper  roller  clearances  are  as  follows: 


Admission  valve  cam  clearance 

Exhaust  valve  cam  clearance 

Fuel  valve  cam  clearance 

Air  starting  valve  cam  clearance 


0.01  inch 
0.01  inch 
0.004  inch 
0 . 036  inch 


The  proper  valve  timing  appears  in  Fig.  92.     Any  change  of 
the  entire  cam  timing  can  be  obtained  by  shifting  the  gears  one 


FIG.  92. — Snow  Diesel.     Valve  timing. 

or  two  teeth,  while  the  alteration  of  an  individual  valve  cam  can 
be  secured  by  the  use  of  a  properly  offsetted  key. 

McEwen  Diesel  Valves. — One  excellent  feature  of  this  hori- 
zontal engine  is  the  provision  of  cages  for  both  the  exhaust  and 
the  admission  valves.  These  cages  and  valves  are  mounted  in 
the  cylinder  head  in  vertical  positions,  as  appears  in  Fig.  70. 
Both  valves  are  of  cast  iron  with  steel  stems;  the  exhaust  valve 
body  is  extended  to  form  a  hood  about  the  lower  part  of  the  stem. 


108 


OIL  ENGINES 


The  two  valves  and  the  admission  valve  cage  are  shown  in  Fig. 
93;  both  valves  have  45-degree  seats.  To  remove  either  cage, 
it  is  only  necessary  to  unship  the  reach-rod  pin  and  lift  out  the 
cage  with  the  rocker  attached. 

The  camshaft  is  driven  by  a  helical  gear  from  the  engine  shaft. 
The  valve  rocker  arrangement  is  outlined  in  Fig.  70.  Each  valve 
has  its  individual  cam,  the  exhaust  cam  roller  being  provided 
with  a  shifting  pin  which  relieves  the  compression  on  starting  the 
engine. 


FIG.  93. — McEwen  Diesel  admission  valve  and  cage. 

Cam  Clearances. — The  valve  cam  clearances  follow: 

Admission  valve  cam.  clearance 0 . 005  inch 

Exhaust  valve  cam  clearance 0 . 03  to  > 

Injection  valve  cam  clearance 0. 001  inch 

Starting  valve  cam  clearance 0. 03  to  >62  mcn 

Valve  Timing. — The  timing  diagram  applicable  to  the  engine 
appears  in  Fig.  94.  These  values  can  be  followed  by  the  opera- 
tor with  a  feeling  that  they  are  correct. 

National  Transit  Diesel  Valves. — -This  engine  has  the  admis- 
sion valve  provided  with  a  cage  while  the  exhaust  valve  has  a 
half-cage,  which  carries  the  valve  spring  and  stem  housing.  The 
latter  valve  does  not  seat  on  the  cage  but  instead  a  removable 
seat  is  set  into  the  cylinder  casting  and  held  in  place  by  machine 
screws,  Fig.  95. 


ADMISSION  AND  EXHAUST  VALVES  109 


FIG.  94. — McEwen  Diesel.     Valve  timing. 

I 


FIG.  95.— National  Transit  Diesel  valves  and  rockers. 


110 


OIL  ENGINES 


The  valves  differ  in  that  the  exhaust  valve  body  is  extended  to 
form  a  guard  around  the  stem.  In  removing  the  valves,  the 
admission  valve  cage  is  first  lifted  off,  and  then  the  exhaust  valve 
spring  and  cap  are  unshipped.  The  exhaust  valve  can  then  be 
raised  through  the  admission  valve  cavity.  If  it  is  desired  to 
remove  the  exhaust  cage,  a  rope  can  be  passed  through  the  valve 
stem  housing  and  tied;  slipping  the  other  end  through  the  admis- 


FIG.  96. — National  Transit  Diesel.     Valve  timing. 

sion  cage  cavity  and  hooking  it  to  a  hoist,  the  exhaust  cage  may 
be  lowered  to  the  floor  or  lifted  into  place  as  the  case  may  be. 
The  false  exhaust  seat  is  difficult  to  remove  when  worn  as  the 
screw  threads  tend  to  burn  and  corrode  fast.  Vigorous  ham- 
mering with  a  long  bar  will  frequently  loosen  the  screws;  kero- 
sene should  always  be  poured  on  the  seat  since  this  will  assist  in 
cutting  away  the  iron  rust  from  around  the  screw  threads. 

Valve  Cam  Mechanism. — Both  the  valves  are  actuated  by 
wiper  type  levers.  These  levers  are  controlled  by  a  single  eccen- 
tric as  shown  in  Fig.  95.  Since  the  contact  between  the  flat 
valve  lever  and  the  rocking  levers  is  a  rolling  one,  the  clearances 
are  not  of  such  serious  moment.  The  correct  timing  of  the  valves 


ADMISSION  AND  EXHAUST  VALVES 


111 


can  be  secured  by  either  shifting  the  eccentric,  or  altering  the 
length  of  the  valve  stems  through  the  agency  of  the  valve  lock- 
nut  caps,  or  by  adjusting  the  length  of  the  valve  reach-rods.  The 
latter  is  the  proper  method  for  securing  any  minor  timing  adj  ust- 
ments.  The  valve  timing  of  this  make  of  engine  appears  in  Fig. 
96.  It  is  apparent  from  Fig.  13  that  the  air  starting  and  fuel- 
injection  cams  are  distinct  from  the  valve  eccentric. 


FIG.  QQA. — National  Transit  1918  design  Diesel  valve  rocker  assembly. 

National  Transit  Diesel,  1918  Model  Valves. — The  later  en- 
gines produced  by  the  National  Transit  Co.  have  a  valve  and 
camshaft  design  radically  different  from  the  one  discussed  above. 
The  valves  are  placed  horizontally  in  the  cylinder  head,  and  both 
are  provided  with  cages.  This  entire  assembly  appears  in  Fig. 
96A.  The  end  of  the  valve  stem  has  an  adjustable  head  which  is 


112 


OIL  ENGINES 


in  contact  with  the  valve  rocker,  and  a  collar  against  which  the 
valve  spring  rests.  No  spring  cap  or  other  bearing  is  provided 
for  the  support  of  the  outer  end  of  the  stem.  However,  the 
cage  sleeve  is  long  and  gives  ample  support. 

Camshaft  Layout. — The  rocker  arms  fulcrum  on  a  short  shaft 
which  is  carried  on  bearings  bolted  to  the  head ;  this  shaft  is  loose 
in  the  bearings  and  is  held  by  the  starting  lever  shown.  The 
rocker  rollers  rest  on  the  cams  which  are  keyed  to  the  short  cam- 
shaft; this  shaft  is  driven  by  the  layshaft  through  bevel  gears. 

The  advantage  of  this  design  lies  in  the  better  cylinder  head 
that  is  permissible  with  horizontal  valves. 

Valve  Timing. — The  timing  of  the  valves  is  the  same  as  applies 
to  the  former  design  and  appears  in  Fig.  96. 


/x%%%^^ 

FIG.  97. — Allis-Chalmers  Diesel  valves  and  rockers. 

Allis-Chalmers  Diesel  Valves  and  Rockers. — The  valve  ar- 
rangement of  this  engine,  Fig.  97,  is  quite  similar  to  the  one  just 
discussed  in  Fig.  95.  The  exhaust  valve,  however,  has  no  re- 
movable seat  since  it  rests  directly  on  the  cylinder-head  casting. 
Use  is  made  of  a  single  eccentric  for  both  valve  actuating; rods. 
In  the  two-cylinder  engines  a  system  of  links  allows  the, one 
camshaft  to  control  the  exhaust  and  .admission  valves  of  both 
cylinders.  The  valve  rockers  have  a  wiping  action  and  conse- 


ADMISSION  AND  EXHAUST  VALVES 


113 


quently  open  and  close  the  valve,  while  the  rocker  is  moving  at 
a  maximum  speed,  without  shock  or  noise.  The  noiseless  valve 
action  is  especially  noticeable  to  one  accustomed  to  the  slam- 
ming noise  of  the  usual  cam-controlled  Diesel  valves.  Since 
this  form  of  valve  actuating  levers  is  used,  no  clearance  is  required 
between  the  lever  and  valve  cap  when  the  eccentric  is  in  its 
extreme  low  position,  beyond  that  necessary  i&r  the  oil  film, 
which  need  not  be  more  than  .001  inch. 

Standard  Fuel  Oil  Engine. — This  engine,  being  of  the  two- 
stroke-cycle  type,  possesses  no  air  admission  or  exhaust  valves. 


Fio.  98. — Standard  Fuel  Oil  Diesel  compressor  and  section. 

The  piston  performs  the  duty  of  both  valves,  uncovering  air 
scavenging  ports  and  exhaust  ports  at  the  forward  end  of  its 
stroke.  The  piston  action,  along  with  the  functioning  of  the 
scavenging  air  valve,  should  properly  fall  within  the  scope  of 
this  discussion  of  engine  valves.  In  Chapter  VI  a  few  words  were 
devoted  to  the  scavenging  piston  which  acts  as  a  compressor 
to  supply  the  scavenging  air  to  the  power  cylinder,  although  the 
means  of  this  accomplishment  were  not  mentioned.  Figure  63 
represents  the  engine  cross-section,  showing  both  the  power  pis- 
ton and  the  scavenging  piston,  which  is  bolted  to  the  former. 
Figure  98  is  a  view  of  the  injection  air  compressor.  The  low- 
pressure  air  piston  is  of  an  hour-glass  shape  and  acts  as  a  valve 
in  directing  the  proper  flow  of  the  scavenging  air.  The  pipe  a 
is  the  air  suction  line  open  to  the  atmosphere.  The  air,  flowing 
in  along  the  pipe  a,  passes  through  the  port  I,  allowing  this  air 
to  enter  the  scavenging  air  cylinder  H,  shown  in  Fig.  63.  As 

8 


114 


OIL  ENGINES 


the  engine  turns  over  this  air  is  compressed,  and  the  continued 
movement  of  the  plug  piston  g,  Fig.  98,  uncovers  the  port  d, 
which  permits  the  air  to  flow  out  through  the  pipe  di  into  a  low- 
pressure  air  receiver,  not  shown.  This  air  is  at  a  pressure  of  8 
to  10  Ibs.  gage.  After  the  fuel  charge  in  the  power  cylinder  fires 
and  the  piston  moves  outward,  the  exhaust  ports  K  are  un- 
covered. At  the  same  time  the  scavenging  air  ports  e  are  also 


FIG.  99. — Standard  Fuel  Oil  engine  two-stroke-cycle  Diesel  fuel  valve  and 
exhaust  port  timing. 

opened.  During  this  interval  the  plug  piston  g  has  moved, 
shutting  off  the  connection  between  the  scavenging  cylinder  and 
the  air-receiver  line  d,  and  has  placed  d  in  communication  with 
the  scavenging  air  ports  e.  The  air,  stored  in  the  receiver, 
rushes  through  the  ports  e,  scavenging  the  power  cylinder  of 
the  exhaust  gases.  It  is  apparent  that  the  successful  functioning 
of  the  entire  air  scavenging  system  depends  on  the  condition  of 
the  air-compressor  piston  or  plug  valve  g. 


ADMISSION  AND  EXHAUST  VALVES 


115 


Valve  Timing. — The  timing  of  the  fuel  valve,  as  well  as  the 
points  of  opening  and  closure  of  the  exhaust  ports,  is  indicated 
in  Fig.  99. 

De  La  Vergne  Type  FD  Diesel  Valves. — This  horizontal 
Diesel  has  the  valves  located  horizontally  in  the  head.  They  are 
driven  by  rockers  which  are  actuated  by  a  camshaft  bolted  to  the 
front  of  the  cylinder  head,  as  appears  in  Fig.  15. 


FIG.  100.— De  La  Vergne  FD  Diesel.     Valve  timing. 

Valve  Timing. — Figure  100  gives  the  valve  timing  of  this 
Diesel.  Individual  units  may  vary  slightly  from  these  values. 

Mclntosh  &  Seymour  Marine  Diesel  Valves  and  Valve 
Cages. — The  admission  and  exhaust  valve  cages  are  made  of  cast 
iron  and  do  not  have  separate  valve  seats.  The  valves  proper 
are  also  of  cast  iron  with  steel  stems  cast  in,  and  are  guided  in 
the  lower  part  of  the  valve  cage  and  do  not  have  an  upper  guide 
as  is  used  in  the  stationary  Diesel  for  the  guiding  of  the  valve. 

Rocker  Arms. — The  various  rocker  arms  are  operated  from 
the  cams  by  means  of  vertical  push-rods,  including  the  air  starter 
and  fuel  valve  rockers,  Fig.  101. 


116 


OIL  ENGINES 


Camshaft. — The  camshaft  is  driven  by  a  set  of  spur  gears 
from  the  crankshaft  at  the  -after  end  and  runs  at  half  the  engine 
speed.  A  double  set  of  cams  is  arranged  side  by  side  in  the 
following  order:  exhaust,  fuel,  starting,  and  admission.  They 
are  keyed  to  the  shaft  and  bolted  together.  Cams  and  rollers 
are  made  of  cast  iron  and  are  chilled  at  the  running  edges. 


°  ADJUSTMENT 
f//e  Corner  fo  give 
^Clearance 


FIG.  101. — Mclntosh  &  Seymour  marine  Diesel.    Valve  arrangement. 

Reversing  and  Operating  Gear. — This  gear  is  located  on  the 
forward  end  of  the  engine.  Two  turns  of  the  reversing  wheel 
shift  the  camshaft  in  a  horizontal  direction  for  either  ahead  or 
astern  rotation.  This  mechanism  is  designed  as  follows:  The 
hand  wheel  turns  a  shaft  to  which  a  bevel  gear  is  keyed,  Fig.  102, 
which  in  turn  rotates  a  large  bevel  gear  D  mounted  on  another 
shaft,  at  right  angles  to  the  first  one,  carrying  a  pinion  which 
operates  a  rack  L  up  and  down.  This  rack  has  an  extension 
which  is  provided  with  a  slot  in  which  a  roller  moves,  which 
roller  is  fastened  to  a  rocker  arm  M  pivoted  around  a  fixed  point. 


ADMISSION  AND  EXHAUST  VALVES 


117 


The  other  end  of  the  lever  is  forked  and  its  arms  fit  in  a  groove 
in  a  sleeve  fastened  to  the  camshaft,  thus  moving  this  shaft  in 


either  direction  at  will.     The  rollers  for  exhaust,  fuel,  and  ad- 
mission are  moved  away  from  the  respective  cams  by  the  rods 


118 


OIL  ENGINES 


I  and  R  at  the  same  time  the  camshaft  is  shifted  longitudinally. 
Starting  is  performed  by  moving  the  lever  0,  which  controls  fuel 
and  starting,  all  the  way  downward,  in  which  event  the  starting 
air  roller  is  brought  in  contact  with  its  respective  cam,  admitting 
air  tq  the  cylinders.  As  soon  as  the  engine  has  turned  over  a  few 
times  on  air,  the  control  handle  0  is  moved  upward  again, 

bringing  the  fuel  admission  at  the 
full-load  position.  It  will  be  un- 
derstood that  the  starting  air  was 
automatically  cut  off  again  as  soon 
as  the  control  lever  reached  the 
" full-load"  mark  on  the  segment. 
When  the  engine  is  run  on  fuel, 
the  reversing  gear  and  the  fuel  regu- 
lations are  interlocked,  and  only 
when  the  control  lever  is  on  STOP 
does  it  become  possible  to  turn  the 
reversing  wheel  as  the  notch  is 
disengaged  from  the  bevel  gear  rim. 
The  control  lever  cannot  be  moved 
unless  the  engine  is  fully  reversed 
either  way. 

Nelseco  Four-cycle  Marine 
Diesel  Valves  and  Valve  Gear. — 
Figure  103  is  a  cross-section  of  this 
marine  Diesel.  The  admission 
valve  is  provided  with  a  cage, 
and  the  exhaust  valve  seats  on  a 
removable  seat  in  the  combustion 
chamber  walls.  The  air  and  fuel 
valves  are  actuated  through  levers 
by  the  starboard  camshaft  while 
the  exhaust  camshaft  is  on  port 
side.  The  two  camshafts  are  driven  by  a  2  to  1  reduction  gear 
from  the  engine  shaft. 

Reversing  Gear. — The  majority  of  these  Diesels  are  equipped 
with  a  gear  for  reversing,  though  some  have  a  direct  reverse 
arrangement  shown  diagrammatically  in  Fig.  104.  The  cam- 
shafts, of  which  there  are  three,  have  spiral  key  ways  cut  in  them. 
Each  shaft  has  a  collar  with  a  spiral  key  which  is  shifted  by  a 
pneumatic  reversing  cylinder.  A  movement  of  the  rocker  A 


SECTION  (£_CYL.   No.  4 
FIG.  103. — Nelseco  marine  Diesel. 


ADMISSION  AND  EXHAUST  VALVES 


119 


throws  the  collars  to  one  side,  thus  turning  the  camshafts  through 
an  angle  that  will  set  the  valve  cams  correct  for  reverse  running. 
Due  to  the  varying  angle  through  which  the  three  sets  of  cams 
must  move,  the  spiral  keyways  do  not  have  the  same  pitch,  thus 
securing  proper  shifting  of  the  cams. 


Ahead'  Astern 

FIG.   104. — Nelseco  four-cycle-engine  reversing  mechanism. 

Valve  Cages. — As  would  appear  from  the  foregoing  discussion, 
all  the  manufacturers  use  cages  on  the  admission  valves  while 
the  practice  is  not  universal  as  regards  the  exhaust  valves. 
There  can  be  no  doubt  that  the  cage  design  is  superior  and  is  of 
advantage  to  the  operator.  When  a  valve  seat  leaks,  a  spare 
valve  and  cage  can  be  used  to  replace  the  defective  parts.  No 
matter  how  thrifty  the  operator  must  be  as  to  the  capital  in- 
vested in  replacement  parts,  it  is  the  height  of  economy  to  carry 
one  extra  admission  and  one  extra  exhaust  valve  with  their  cages. 

Water-cooled  Cages  and  Valves. — Due  to  the  severe  tempera- 
tures of  the  exhaust  gases  as  they  pass  through  the  exhaust  valve 
cage,  water-cooling  of  the  valve  stem  housing  is  well-nigh  im- 
perative in  engines  above  12-inch  cylinder  bore.  All  manufac- 
turers provide  for  this  stem  cooling  even  though  a  valve  cage  is 
not  included  in  the  valve  design.  It  is  clear  that  the  circulation 
of  water  must  be  positive  if  the  sticking  df  the  stem  is  to  be 


120  OIL  ENGINES 

avoided.  Where  the  water  carries  any  considerable  percentage 
of  mineral  salts,  there  is  a  decided  tendency  toward  the  scaling- 
up  of  the  cooling  space,  which  is,  at  best,  of  small  volume.  Con- 
sequently, each  time  the  exhaust  cage  is  removed  the  water- 
cooling  cavity  should  be  filled  with  a  10  per  cent,  muriatic  acid 
solution  and  afterward  thoroughly  flushed  out  with  a  stream  of 
water  under  at  least  20  Ibs.  pressure.  Since  the  engine 
has  already  extracted  the  available  portion  of  the  heat  of  the 
gases,  there  is  no  loss  occasioned  by  a  cool  valve  cage;  the  cage- 
cooling  water  discharge  should  be  kept  below  120°  Fahrenheit 
as  a  low  temperature  improves  the  valve  action.  Even  at  this 
temperature  of  the  discharge  the  valve  stem  is  actually  much 
hotter,  and  the  lubricating  oil  often  forms  a  gumming  deposit 
that  makes  the  valve  motion  erratic.  A  little  kerosene  should  be 
injected  along  the  stem  after  each  shut-down. 

Water-cooled  Valves. — On  some  of  the  larger  engines  water- 
cooling  of  valves,  especially  the  exhaust  valve,  is  essential  to  the 
successful  functioning  of  the  valve.  The  water  is  customarily 
introduced  at  the  side  of  the  stem  and  flows  down  to  the  body, 
where  it  enters  a  central  tube  which  carries  it  to  a  connection  at 
the  end  of  the  valve  stem.  With  both  water-cooled  valves  and 
water-cooled  cages  the  water  must  be  circulated  before  the  engine 
starts  firing.  If  this  matter  is  deferred  until  the  engine  has 
warmed  up,  the  sudden  chilling  of  the  parts  by  the  cold  water  will 
invariably  produce  a  fracture. 

Pitting  and  Corrosion  of  Valve  Seats. — Both  chemical  and 
mechanical  reactions  cause  pitting  and  corrosion  of  the  valve 
seats,  particularly  of  the  exhaust  valve.  The  pounding  of  the 
valves,  as  they  close  rapidly,  produces  a  series  of  minute  surface 
fractures  that,  in  time,  allow  small  portions  of  the  metal  to  flake 
off,  giving  the  effect  of  pits.  A  more  prevalent  result  of  the  valve 
hammering  is  the  formation  of  grooves  around  the  seat.  These 
serve  as  recesses  to  hold  carbon  deposits,  which  soon  cause  the 
valve  to  leak. 

The  chemical  action  of  the  exhaust  gases,  especially  when  any 
considerable  amount  of  sulphur  is  contained  in  the  fuel  oil, 
rapidly  forms  pits  that  enlarge  to  some  magnitude.  This  manner 
of  pitting  is  responsible  for  the  majority  of  leaking  valves.  It 
can  be  largely  offset  by  more  rigid  fuel  specifications,  which 
exclude  all  oils  having  a  sulphur  content  above  1  per  cent,  and 
all  oils  possessing  even  a  trace  of  acid. 


ADMISSION  AND  EXHAUST  VALVES 


121 


Cleaning  Valves. — Once  a  month  each  valve  and  cage  should 
be  removed  for  inspection  and  cleaning.  A  regular  schedule  can 
be  followed  whereby  the  valves  of  one  cylinder  are  removed  each 
week;  in  a  four-cylinder  engine  this  gives  a  monthly  inspection, 
while  in  a  three-cylinder  engine  an  inspection  every  three  weeks 
is  secured.  When  the  engine  is  a  single-  or  double-cylinder  unit, 
the  schedule  should  be  arranged  so  that  the  monthly  examination 
is  obtained.  At  these  inspections  the  valve  and  cage  should  be 
completely  disassembled  and  thoroughly  cleaned  with  kerosene, 

washing  off  with  gasolene.     If  a  valve         f x 

and  cage  is  kept  on  hand,  the  old  one 
can  be  cleaned  at  leisure.  This  spare 
set  is  very  essential  where  an  engine 
operates  almost  continuously.  The 
time  required  for  removal  and  re- 
placement of  cage  and  valve  should 
not  exceed  thirty  minutes  when  the 
engine  room  force  is  well  organized. 

Grinding  Valves. — If  the  valve  seat 
becomes  rough,  allowing  the  com- 
pression to  escape,  it  must  be  re- 
ground.  Where  the  valve  seats  in  a 
cage  the  unit  is  disassembled.  The 
valve  and  dashpot  or  spring  cap,  as 
it  is  more  popularly  termed,  is  re- 
placed in  the  cage  with  a  light  spring 
resting  between  the  valve  body  and 
the  stem  housing,  along  the  lines  of 
Fig.  105.  The  cage  is  inverted, 
placed  on  some  form  of  support,  and 
the  valve  pin  wrench  is  then  set  in  position.  The  spring  raises 
the  valve  off  the  cage  seat  until  a  slight  downward  pressure  is 
exerted  by  the  man  doing  the  regrinding.  A  mixture  of  emery 
flour  and  oil  or  emery  flour  and  vaseline  should  be  coated  over 
the  valve  face  and  the  valve  rotated  back  and  forth.  The 
valve  should,  in  no  case,  be  completely  revolved;  the  rotation 
or  movement  should  "cover  a  trifle  more  than  a  quarter  circle. 
After  rotating  a  few  minutes,  the  valve  should  be  moved  another 
90  degrees  and  the  rotation  renewed.  This  grinds  every  por- 
tion of  the  valve  face  to  conform  to  the  entire  seat  of  the  cage. 
As  the  operator  grinds  the  valve,  he  should  release  the  down- 


FIG.  105. — Regrinding  valves. 


122 


OIL  ENGINES 


ward  pressure  on  the  valve,  allowing  it  to  rise  from  the  seat. 
This  serves  to  distribute  the  emery  paste  over  the  entire  face. 
If  this  is  not  observed,  the  paste  forms  at  the  edges  only,  causing 
the  valve  seat  to  be  ground  concave. 

The  operator  need  not  secure  a  ground  seat  over  the  entire 
valve  face.  A  narrow  contact  J-f  g-inch  wide  is  ample;  in  fact,  a 
line  contact  of  ^2~mcn  width  is  as  serviceable  a  gas  seal  as  is 
a  wider  space.  After  the  seat  is  sufficiently  ground,  the  emery 


FIG.   106. — Valve  seat  reamer. 

paste  can  be  removed.  The  valve  should  then  be  rotated  without 
any  paste  between  the  two  surfaces;  this  metal  to  metal  grinding 
or  rubbing  will  make  the  area  of  contact  as  smooth  as  a  mirror 
and  prolongs  the  tightness  of  the  valve. 

When  the  valve  becomes  so  pitted  or  grooved  that  grinding 
will  not  be  of  any  avail,  the  cage  and  valve  faces  must  have 
a  light  cut  taken  off  their  surfaces.  The  valve  can  be  centered 
in  a  lathe  and  a  finishing  tool  used,  making  the  cut  as  light 
as  possible.  To  reface  the  cage  a  refacing  machine,  similar  to 
a  rose  reamer,  is  necessary.  This  reamer  must  have  a  stem 
resting  in  the  valve-stem  housing  to  hold  the  reamer  square 
with  the  valve  stem.  Most  manufacturers  are  in  a  position 


ADMISSION  AND  EXHAUST  VALVES 


123 


to  supply  this  machine,  although  any  machine  shop  can  build 
one  like  the  sketch  in  Fig.  106.  The  cutting  head  should  be  of 
tool  steel  while  the  stem  can  be  either  of  tool  steel  or  machine 
steel.  The  latter  is  preferable  since  the  cutting  head  can  be 
hardened  and  the  machine-steel  stem  turned  to  bring  the  cutter 
concentric. 

Few  plants  possess  any  stand  to  hold  the  cage  other  then  a 
wooden  box.  The  box  is  a  poor  accessory  since  it  is  almost 
impossible  to  seat  the  irregular-formed  cage  on  it  with  any  feel- 
ing of  security.  A  wooden  grinding  stand,  similar  to  Fig.  107, 


Jo  move  Bench  the 
End  is  Pinched  up 
and  the  Axle,  which 
Swings  on  the  Arm 
is  Pushed underthe 
Box. 


FIG.  107. — Bench  for  grinding  and  reaming  valve  cages. 


can  be  made  during  odd  hours  and  certainly  repays  all  labor 
spent  on  it.  The  opening  in  the  top  should  conform  to  the  shape 
of  the  cage  while  the  two  stud-bolts  should  fit  into  the  regular 
stud-bolt  holes  in  the  cage.  With  such  an  apparatus  an  engineer 
can  sit  down  while  grinding,  thus  lessening  as  much  as  possible 
the  labor  involved  in  this  operation. 

Valve  Timing. — In  timing  valves  the  first  step  is  the  establish- 
ment on  the  flywheel  of  the  points  of  dead-center  of  the  cranks. 
The  simplest  method  of  marking  the  dead-centers  is  to  use  a 
steel  trammel  having  both  ends  pointed.  A  steel  block,  with 
a  counter  punch  mark  on  the  surface,  can  be  inset  into  the  founda- 


124 


OIL  ENGINES 


tion,  being  held  by  lead  or  cement  grouting,  Fig.  108.  To 
establish  the  flywheel  position,  when  the  crank  is  on  upper  dead- 
center,  one  of  the  valve  cages  can  be  removed  and  the  distance 
from  the  surface  of  the  cylinder  head  to  the  piston,  when  the 
piston  is  approximately  at  upper  dead-center,  can  be  measured 
and  a  trammel  mark  made  on  the  flywheel  rim.  The  wheel 
is  then  turned  on  over  past  dead-center  until  the  piston  is  again 
the  same  distance  from  the  cylinder  head.  A  second  mark 
is  placed  on  the  flywheel  rim;  the  bisection  of  the  distance  be- 


FIG.   108. — Locating  crank  positions  on  the  flywheel. 

tween  the  two  trammel  marks  gives  the  exact  dead-center  for 
the  piston  in  question.  A  second  but  not  so  exact  a  method  is 
the  use  of  a  spirit  level  on  the  crank  throws;  this,  of  course,  is 
impossible  if  the  throws  are  not  machined  accurately  on  all  four 
sides.  The  center  mark  should  be  placed  on  the  flywheel  rim 
and  stamped  with  the  cylinder  number,  as  example  2TC,  in- 
dicating top  dead-center  of  No.  2  cylinder.  The  same  procedure  is 
followed  on  all  the  cylinders  for  both  top  and  bottom  dead-centers. 
These  center  positions  be;ng  determined,  the  next  step  is  the 
checking  of  the  exhaust  valves.  The  engine  should  be  turned  over 
until  the  piston  of  the  cylinder  in  question  is  about  50  degrees  from 


ADMISSION  AND  EXHAUST  VALVES  125 

bottom  dead-center.  A  steel  tape  line  can  be  used  to  measure  the 
distance  on  the  flywheel  rim  from  the  bottom  dead-center  line  to 
the  point  of  correct  exhaust  valve  opening.  Since  the  timing  given 
is  in  degrees,  the  value  must  be  transformed  into  inches  on  the  fly- 
wheel circle.  Presuming  the  wheel  is  8  feet  in  diameter,  the  cir- 
cumference being  302  inches,  each  degree  represents,  very  closely, 
%-inch.  If  the  proper  opening  of  the  exhaust  is  42  degrees 
ahead  of  bottom  dead-center,  a  distance  of  35  inches  is  set  off 
ahead  of  the  dead-center  mark.  This  is  spotted  and  stamped 
E20;  that  is,  exhaust  opening  for  No.  2  cylinder.  The  flywheel 
should  then  be  turned  slowly  until  the  trammel  cuts  this  E2O 
mark.  The  exhaust  cam  rocker  should  be  firmly  in  contact 
both  with  the  cam  and  with  the  valve  stem.  To  be  doubly 
certain,  the  adjusting  screw  on  the  rocker  should  be  backed  off 
and  brought  up  again  until  the  operator  can  feel  the  resistance 
of  the  valve  spring  against  the  screw.  In  case,  while  revolving 
the  wheel,  the  mark  E20  is  passed,  the  valve  should  not  be 
checked  by  bringing  the  wheel  back  to  the  mark.  Instead,  the 
wheel  should  be  brought  back  past  the  mark  at  least  12  inches 
and  then  again  turned  until  the  trammel  cuts  the  mark.  This 
removes  all  effect  of  any  back  lash  that  might  exist  in  the  cam 
gears.  The  same  process  is  followed  in  checking  the  exhaust 
closing  position.  After  this  is  accomplished,  the  exhaust  valve 
settings  of  the  other  cylinders  are  checked,  the  flywheel  being 
properly  marked  for  each  position.  The  admission  valves 
should  next  be  gone  over  in  proper  sequence,  and  all  points 
should  be  indicated  on  the  wheel  for  future  reference. 

In  event  any  of  the  valves  fail  to  check  up  correctly,  the  oper- 
ator is  confronted  with  the  question  as  to  the  method  of  changing 
the  setting.  If  the  discrepancy  is  only  a  few  inches,  the  clearance 
between  the  cam  and  the  valve  rocker  can  be  changed,  bringing 
the  setting  back  to  the  stated  values.  If  the  valve  opens 
vastly  early,  or  late,  the  only  recourse  is  the  shifting  of  the  cams 
by  the  use  of  an  offset  key.  This  condition  is  encountered  in  old 
engines  only.  In  these  engines  quite  often  the  entire  valve 
layout  is  timed  late.  This  is  attributable  to  the  wear  in  the  cam 
gear  teeth  and  can  be  partially  corrected  by  advancing  the  cam 
gear  one  or  two  teeth. 

The  average  operator,  until  he  is  very  familiar  with  engine 
timing,  does  well  to  time  the  exhaust  and  admission  valves  of 
one  cylinder  before  proceeding  to  any  of  the  valves  of  the  other 


126  OIL  ENGINES 

cylinders.  There  is,  in  this  way,  little  danger  of  becoming 
confused  as  to  the  proper  stroke  upon  which  the  valve  should 
function-  The  trained  operator  customarily  checks  the  valves 
as  they  come  in  sequence.  For  example,  the  exhaust  opening 
of  one  cylinder  will  be  set,  then  the  admission  closing  of  a  second 
cylinder  will  be  checked.  This  reduces  the  time  occupied  in 
going  over  the  valves  by  at  least  75  per  cent.  The  checking 
and  setting  of  the  fuel  valves  will  be  taken  up  in  the  chapter  on 
fuel  valves. 

Leaky  Valves. — A  leaky  admission  valve  is  readily  detected 
by  placing  one's  ear  close  to  the  intake  nipple  or  screen.  If 
the  leak  is  from  a  scored  seat,  a  whistling  noise  will  be  heard; 
this  whistling  increases  in  volume  as  the  scoring  becomes  more 
pronounced. 

A  leaky  exhaust  valve  is  more  difficult  to  detect.  The  best 
method  is  to  place  the  engine  in  that  position  where  both  the 
admission  and  exhaust  valves  are  closed;  that  is,  at  the  beginning 
of  the  power  stroke.  The  injection  air  line  valve  should  be 
"  cracked,"  allowing  a  small  amount  of  air  to  blow  into  the  cylin- 
der through  the  fuel  injection  valve.  If  the  exhaust  leaks,  the 
air  can  be  heard  flowing  through  the  valve.  This  same  pro- 
cedure will  also  locate  admission  valve  leaks.  While  the  en- 
gine is  running,  a  smoky  exhaust  an  "  a  decrease  in  power  are  often 
due  to  a  leaky  exhaust  valve. 


CHAPTER  IX 


Rotary  Fuel 
Valve  V 


FUEL  INJECTION  VALVES 

TYPES.     ACTION.    ADJUSTMENT.     REPAIRS 

Injection  Design  of  the  Original  Diesel  Engine. — Dr.  Diesel 
in  his  first  patent  application,  made  no  mention  of  any  mechan- 
ism for  the  forcible  injection  of  the  fuel.  The  fuel  contemplated 
was  coal  dust,  and  this  was  to  be  deposited  in  a  pocket  of  the 
rotary  valve  V,  which,  in  revolving,  dropped  the  charge  into  the 
cylinder.  A  schematic  outline  of 
this  fuel-conveying  apparatus  is 
shown  in  Fig.  109. 

This  design  was  never  followed 
in  an  actual  engine  since  it  was 
early  seen  that  it  would  not  prop- 
erly deliver  the  fuel  charge.  Fur- 
therm  re,  the  plan  of  using  coal 
dust  was  abandoned  in  favor  of  oil. 
Dr.  DiesJ-  in  conjunction  with 
the  M.  A.  .J.  Co.  of  Germany, 
adopted  the  idea  of  employing  a 
blast  of  air  to  break  up  the  oil 
charge  and  deliver  it  into  the 
cylinder. 

Injection  Action. — For  the  bene- 
fit of  those  unacquainted  with 

the  functioning  of  the  fuel  injection  valve  the  following  brief 
explanation  is  given.  The  charge  of  fuel  oil  is  pumped  into  a 
receptacle  called  the  fuel  valve  by  some  form  of  pump.  An 
air  compressor  delivers  a  charge  of  pure  air  at  about  900  Ibs. 
gage  to  this  injection  device.  At  the  proper  moment  in  the 
engine's  cycle  the  needle  valve  of  the  injection  device,  or  fuel 
valve,  is  opened,  connecting  the  cylinder  with  the  fuel  supply. 
The  high-pressure  air  then  rushes  into  the  cylinder,  carrying 
the  oil  charge  with  it.  This  fuel,  as  it  is  forced  through  a  device 

127 


FIG.  109.— Fuel  feeding  ar- 
rangement, Dr.  Diesel's  original 
patent. 


128 


OIL  ENGINES 


called  the  atomizer,  which  is  located  in  the  valve  housing  or 
cage,  is  broken  up  into  fine  fog-like  particles  that  will  ignite 
when  intermingled  with  the  cylinder  charge  of  air,  which  is  at 
a  high  temperature.  Figure  110  shows  such  an  elementary 
form  of  fuel  valve  where  D  is  the  valve  stem;  A,  the  oil  line; 
C,  the  air  line;  B,  the  atomizer;  and  E,  the  opening  into  the 
cylinder. 

It  is  evident  that  the  fuel  valve  has  two  main  functions. 
First,  it  must  allow  the  oil  charge  to  be  introduced  into  the  engine 
cylinder  or  combustion  chamber  at  the  proper  time.  Second, 

it  atomizes  or  breaks  up  the  stream  of 
oil  in  such  a  thorough  manner  as  to 
occasion  ignition.  The  cylinder  tem- 
perature is  high;  the  value  correspond- 
ing to  550  Ibs.  compression  pressure 
should  be  at  least  1000°  Fahrenheit, 
when  the  engine  is  cold;  after  warming 
up,  the  temperature  would  be  well 
above  1400°  Fahrenheit.  If  the  oil 
charge  was  injected  in  a  solid  mass 
into  this  highly  heated  air,  the  oil 
would  vaporize  and  burn  but  at  a  very 
slow  rate.  The  air  would  not  be 
thoroughly  mixed  with  the  oil,  and  the 
combustion  would  occur  only  on  the 
surface  of  the  oil  mass,  in  exactly  the  same  manner  as  a  pool  of  oil 
burns  when  ignited.  In  this  is  seen  an  example  of  the  so-called 
" surface  ignition"  employed  in  hot-bulb  engines.  The  objection 
to  this  method  lies  in  the  slow  rate  of  combustion  and  in  the  loss 
of  fuel  which  escapes  as  unburned  gas  vapors.  If  the  oil  charge 
is  separated  into  many  minute  particles,  more  surface  area  is 
presented  to  the  air.  If  this  oil  separation  process  is  to  be 
successful,  the  fuel  valve  must  be  provided  with  some  means 
whereby  the  oil  is  broken  into  particles  and  mixed  with  the 
injection  air  before  the  oil  enters  the  engine  cylinder. 

The  theory  of  the  present-day  Diesel  contemplates  the  intro- 
duction of  the  fuel  at  a  rate  which  will  allow  the  combustion  to 
be  carried  on  at  constant  pressure.  If  the  oil  charge  was  in- 
jected at  a  high  rate,  the  combustion  would  partake  of  the  nature 
of  an  explosion;  the  indicator  card  would  then  resemble  an 
Otto-cycle  engine,  and  the  combustion  line  would  be  in  the  form 


VALVE' 
SE/1T 


FIG.  110. — Fuel  valve, 
closed  type. 


FUEL  INJECTION  VALVES  129 

of  a  sharp  peak,  somewhat  like  Fig.  215.  If  the  combustion  is 
to  be  at  a  constant  pressure  rate,  the  flow  of  oil  through  the 
fuel  valve  must  be  gradual.  The  two  main  offices  the  valve 
performs  are  that  of  "braking,"  or  offering  a  resistance  to  the 
oil  flow,  and  that  of  thoroughly  atomizing  the  charge.  The 
latter  would  not  be  difficult  of  achievement  if  there  were  no 
other  considerations  entering  into  the  problem.  The  same  con- 
ditions prevail  as  to  the  "braking"  action.  If  this  "braking" 
effect  is  obtained  by  the  imposition  of  a  series  of  improperly 
designed  baffle  plates  or  disks,  the  air  pressure  required  to  force 
the  oil  through  these  resistances  may  become  so  great  as  to  make 
the  method  impractical.  The  desirable  fuel  valve  is  one  that 
thoroughly  atomizes  the  fuel  and  exercises  a  control,  or  a  "brak- 
ing" action,  over  the  fuel  charge  without  any  great  loss  of  air 
pressure  through  the  valve.  Many  designs  have  been  used, 
all  of  which  fail  to  completely  fulfill  the  above  conditions. 

Classes  of  Atomizers  or  Fuel  Valves. — The  many  fuel  valves 
employed  on  the  various  makes  of  Diesel  engines  fall  into  two 
classes — the  closed-nozzle  and  the  open-nozzle  valves.  The 
former  is  the  one  adopted  on  the  pioneer  Diesels  and  is  found 
on  all  vertical  engines  of  the  present  day;  in  fact,  this  is  necessary 
for  structural  reasons.  The  open  nozzle,  known  in  Europe  as 
the  Lietzenmayer  nozzle,  is  largely  used  on  the  horizontal 
engines,  both  of  the  domestic  and  foreign  manufacture. 

Open-nozzle  Fuel  Valve. — -In  the  design  of  this  nozzle,  or  fuel 
valve,  the  needle  valve  controls  the  flow  of  air  to  the  atomizer 
tip,  this  needle  valve  being  opened  at  the  proper  time  by  a  cam- 
actuated  rocker.  Between  the  valve  and  the  cylinder  is  inter- 
posed a  small  cavity,  or  enlargement  of  the  passage  to  the  cylin- 
der; into  this  cavity  is  deposited  the  fuel  charge.  Since  the  fuel 
is  pumped  during  the  suction  or  exhaust  stroke  of  the  piston, 
the  fuel  pump  works  against  only  a  few  pounds  pipe-resistance 
pressure.  This  enables  the  governor  to  be  very  sensitive  in 
action  since  the  reaction  of  the  pump  is  at  a  minimum.  At  the 
proper  time  the  needle  valve  is  opened,  and  the  air  from  the 
compressor,  as  it  sweeps  along  the  passage  to  the  cylinder,  picks 
up  the  oil  charge  and  carries  it  into  the  cylinder.  The  swirling 
of  the  air  serves  to  thoroughly  break  up  the  mass  of  the  fuel; 
this  is  further  increased  by  perforated  disks  or  other  devices  at 
the  nozzle  tip.  Figure  111  outlines  this  class  of  injection  valve. 
It  would  appear  that  the  duration  of  the  fuel  injection  would  be 


130 


OIL  ENGINES 


FIG.   111. — Open  nozzle  fuel   valve, 
elementary  form. 


in  exact  ratio  to  the  amount  of  oil  deposited  in  the  atomizer  and 
that  the  first  particles  of  oil  entering  the  cylinder  should  be  as 
completely  nebulized  as  are  the  last  few  oil  droplets.  In  actual 
practice  the  air,  when  it  strikes  the  fuel  charge,  produces  slugs 
of  oil  that  enter  the  cylinder  in  an  unatomized  condition.  Where 

perforated  disks  intercept  the 
slugs,  as  in  some  designs,  the 
entire  charge  is  satisfactorily 
broken  up.  The  only  real  ob- 
jection the  operator  can  well 
offer  is  the  rapid  carbonization 
of  the  fuel  passage  and  atomizer 
disks;  this  can  be  attributed 
to  the  absorption  of  heat  from 
the  combustion  chamber  since 
the  temperature  in  the  nozzle 
tip  fairly  approaches  that  ex- 
isting in  the  cylinder  on  the 
compression  stroke.  This  neces- 
sitates a  more  frequent  cleaning  of  the  atomizer  than  is  re- 
quired by  a  closed  type  of  nozzle. 

The  open-type  valve  is  of  advantage  where  dirty  oil  is  burned. 
Since  nothing  but  pure  air  passes  the  needle  valve,  the  scoring 
of  the  valve  seat,  so  prevalent  with  the  closed-nozzle  fuel  valve, 
is  entirely  absent.  Consequently,  this  valve  requires  less  than 
half  as  much  regrinding  as  does  the  closed  type. 

Closed-nozzle  Fuel  Valve. — The  earlier  Diesels  employed  the 
closed  nozzle,  and  it  was  exclusively  used  on  all  Diesels  until 
five  or  so  years  ago.  Figure  110  outlines  the  basic  principle  of 
this  type  of  nozzle.  The  fuel  valve  has  a  body  in  which  a  cavity 
is  formed,  enclosing  the  atomization  device.  The  fuel  needle 
valve  is  seated  below  this  device  and  is  actuated  by  a  cam- 
controlled  lever.  The  interior  of  the  fuel  valve  is  in  connection 
with  the  air  line  through  the  passage  and  is  at  all  times  under 
an  air  pressure  of  900  or  more  Ibs.  per  sq.  inch.  The  fuel 
pump  forces  the  oil  charge  through  the  line  A,  the  oil  settling 
around  the  valve  stem  at  E  above  the  valve  seat.  When  the 
needle  valve  opens,  the  compression  pressure  of  the  engine  is 
around  500-550  Ibs.,  while  the  air  pressure  in  the  valve  body  is 
about  900  Ibs.  This  pressure  difference  results  in  a  rapid  flow  of 
the  air  into  the  cylinder.  The  air  charge  forces  the  oil  along  with 


FUEL  INJECTION  VALVES  131 

it,  and,  in  passing  through  the  tortuous  passages  of  the  atomizer 
disks,  the  oil  is  completely  nebulized. 

This  form  of  fuel  valve  has  the  advantage  of  depositing  the 
oil  in  a  receptacle  entirely  isolated  from  the  influence  of  the  hot 
compressed  air  in  the  cylinder.  Furthermore  part  of  the  oil, 
being  immediately  around  the  valve  tip,  enters  the  cylinder 
ahead  of  the  air  and  ignites,  even  though  it  is  not  thoroughly 
atomized.  This  primary  ignition  provides  a  flame  to  fire  the 
remainder  of  the  oil,  which  enters  the  cylinder  at  a  somewhat 
low  temperature  due  to  the  expansion  of  the  air  charge  at  the 
valve  tip.  Unfortunately,  with  many  closed-nozzle  designs,  an 
entirely  too  great  a  percentage  of  the  fuel  enters  the  cylinder 
ahead  of  the  air;  in  some  it  appears  that  all  the  oil  is  forced  ahead 
of  the  air.  If  the  disks  are  designed  with  perforations  of  small 
diameter  to  enable  the  air  to  mix  with  the  oil,  the  " braking"  or 
resistance  of  the  atomizer  is  increased  since  the  disks  are  entirely 
filled  with  oil  at  full  load.  This  compels  the  employment  of  a 
higher  injection  pressure,  or  the  time  interval  of  fuel  injectior 
is  prolonged.  On  low  loads,  with  small  perforations,  the  fuel 
charge  is  of  small  weight  and  does  not  flow  down  around  the 
valve  seat.  The  consequence  is  that  the  first  part  of  the  injec- 
tion consists  of  air  only,  which,  in  expanding,  chills  the  nozzle 
tip  and  housing.  This  delays  the  combustion,  producing  a 
smoky  exhaust. 

Hardly  any  two  Diesel  manufacturers  follow  the  same  design 
in  the  fuel  valve,  although  there  is  some  degree  of  similarity 
in  a  few  designs,  especially  of  the  open-nozzle  type. 

American  Diesel  Co. — One  of  the  pioneer  fuel  valves  was  that 
of  the  American  Diesel  engine.  This  injection  device  was 
contained  in  a  cast-iron  housing,  which  was  bolted  to  the  side 
of  the  cylinder  head,  as  shown  in  Fig.  112. 

The  needle  valve  is  opened  by  the  bracket  lever  shown,  which, 
in  turn,  receives  its  motion  from  a  reach-rod  and  cam,  the  latter 
being  mounted  on  the  engine  camshaft.  The  closure  of  the 
needle  valve  is  accomplished,  as  is  the  universal  practice,  by  a 
spring,  which  has  been  compressed  by  the  opening  of  the  valve. 
.The  housing  of  the  fuel  valve  carries  the  needle  valve,  which  is 
surrounded  by  the  atomizer  body.  This  atomizer  is  similar  to  Fig. 
113.  The  fuel  enters  the  fuel  valve  housing  or  cage  through  the 
passage  A  and  flows  along  the  recess  between  the  atomizer  and  the 
valve  body  until  it  reaches  the  front  or  valve  end  of  the  atomizer. 


132 


OIL  ENGINES 


The  recess  is  enlarged,  at  this  point,  to  include  the  entire  circumfer- 
ence of  the  atomizer.  From  this  recess  or  ring  a  series  of  minute 
passages  lead  to  the  needle  valve  immediately  above  the  valve 
seat.  The  injection  air  enters  the  housing  at  D  and  flows 


D  ,/tlR 


FIG.   112. — American  Diesel  fuel  valve  assembly. 

around  the  atomizer,  behind  the  oil;  it  also  fills  the  space  about 
the  needle  valve  stem.  When  the  valve  C  opens,  the  flow  of  air 
around  the  stem  results  in  a  drop  in  pressure  from  the  back 
of  the  valve  toward  the  valve  tip.  The  air  pressure  behind 
the  oil  charge,  on  account  of  the  larger  volume,  remains  practi- 


,'OilfJ//s  fh/s  Groove  and  is 
p/  forced  through  Ho/es  by 
•  i  Suction  as  we// as  by  Pressure 


1 


44 

^ 

-<— 

/ufi 

^^'x''' 

\ 

,^-"~^~ 

/ 

/ 

\ 

i      > 

,p* 

—              -«  —  <?//'. 

r. 

^>, 

1 

z&- 

^ 

FIG..  113.  —  American  Diesel  atomizer. 


cally  constant  and  at  a  higher  value  than  the  pressure  around 
the  valve  seat.  This  pressure  difference  forces  the  oil  through 
the  small  ports  E  into  the  stream  of  high-  velocity  air  rushing 
through  the  needle  valve  opening.  The  air  thoroughly  separates 
the  oil  into  minute  particles;  this  breaking-up  process  is  further 
intensified  by  the  flow  of  the  oil  and  air  through  the  openings  in 
the  nozzle-tip  plate  F  between  the  valve  seat  and  the  cylinder. 
The  disadvantage  of  the  valve  lies  in  the  chilling  effect  of  the 
air  charge.  The  design  allows  a  considerable  part  of  the  air 


FUEL  INJECTION  VALVES  133 

to  enter  the  cylinder  ahead  of  the  oil;  since  there  is  no  resistance 
from  an  oil  body  present,  this  air  attains  a  high  velocity  and,  in 
expanding,  lowers  the  temperature  of  the  nozzle  tip  as  well  as 
exerts  a  similar  effect  upon  the  air  which  has  been  compressed 
in  the  cylinder. 

The  fuel  valve  is  equipped  with  a  by-pass  valve  of  the 
screw-needle  type;  this  valve  is  for  the  purpose  of  draining  the 
valve  cage  of  any  oil.  In  stopping  the  engine,  the  by-pass  valve 
is  opened  and  the  oil  flows  through  the  valve  back  to  the  storage 
tank.  The  lack  of  fuel  then  causes  the  engine  to  stop.  In 
starting  the  engine,  the  fuel  pump  is  operated,  by  a  hand  crank, 
until  oil  appears  at  the  by-pass  overflow,  indicating  the  fuel  line 
is  free  from  air.  The  by-pass  valve  is  then  closed. 

Timing  of  Fuel  Valve. — The  fuel  valve  of  the  American  Diesel 
engine  should  be  timed  as  outlined  in  Fig.  79.  The  fuel  valve 
cam  has  an  adjustable  tool-steel  nose,  the  position  of  which  can 
be  varied  to  secure  proper  valve  opening. 

Adjustment  and  Repair.  By-pass  Valve. — The  American 
Diesels  in  service  have  been  operating  a  number  of  years,  and  conse- 
quently frequent  repairs  are  to  be  expected.  One  defect  that 
will  early  develop  is  the  leaking  of  the  by-pass  valve.  The  valve 
is  of  the  needle  type,  and  the  corrosion  of  the  point  allows  oil 
to  seep  at  all  times.  This  can  be  eliminated  by  redressing  the 
point  of  the  valve,  followed  by  a  regrinding. 

Needle  Valve. — The  needle  valve  has  a  rounded  end  which 
seats  on  a  bevel  surface  of  the  atomizer  shell.  Ordinarily  the 
valve  is  made  of  toben  bronze  and  wears  rather  rapidly.  To 
regrind  the  valve,  the  end  should  be  rounded  and  all  rough  spots 
removed.  The  valve  can  then  be  inserted  into  the  atomizer, 
being  coated  with  extra  fine  emery  paste  and  ground  to  a  proper 
contact  with  the  seat.  After  a  number  of  regrindings  the  valve 
stem  becomes  too  short  to  afford  any  initial  compression  of  the 
valve  spring.  If  a  washer  is  placed  between  the  spring  and  cap, 
the  spring  will  be  compressed  on  assembling,  and  the  valve  made 
serviceable  again.  Since  the  bronze  stems  are  rather  expensive 
many  plants  use  a  cold  rolled  steel  valve  stem  with  the  lower 
part  of  bronze  screwed  into  the  steel  stem.  In  case  wear  shortens 
the  stem  beyond  the  ability  of  washers  to  cope  with  the  spring 
compression,  the  bronze  tip  only  need  be  replaced. 

Valve  Stem  Stuffing-box. — The  gland  of  the  valve  stem 
stuffing-box  is  rather  weak,  while  the  stuffing-box  is  very  shallow. 


134 


OIL  ENGINES 


The  air  will  blow  out  along  the  stem,  and  in  tightening  the  gland 
stud-nuts  the  ears  of  the  gland  will  invariably  bend.  If  the 
stuffing-box  were  deeper,  enough  packing  could  be  inserted  to 
withstand  the  air  pressure.  The  only  available  remedy  is  the 
substitution  of  heavier  glands,  enabling  more  pressure  to  be 
exerted  on  the  nuts.  The  packing  used  is  vulcanbestos  and  wears 
away  rapidly.  In  renewing  the  packing,  the  rings  should  be 
soaked  in  oil  for  at  least  twenty-four ; hours.  When  in  use,  the 
valve  stem  must  be  lubricated  frequently  to  maintain  the  packing 
in  a  pliable  condition.  The  fuel  valve  disk,  which  lies  between 
the  valve  seat  and  the  cylinder,  carbonizes  very  heavily  when  a 
a  low  gravity  fuel  is  burned.  A  lye  solution  will  loosen  this 
deposit. 

Busch-Sulzer  Type  B  Diesel.— The  fuel  valve  of  this  Diesel, 
with  its  rocker  mechanism,  appears  in  Fig.  114,  while  Fig.  115 


Running 
Position 


FIG.  114.— Fuel  valve  arrangement  Busch-Sulzer  type^B  Diesel. 


FUEL  INJECTION  VALVES 


135 


gives  a  view  of  the  lower  part  of  the  same  valve.  The  valve  con- 
sists of  a  cast-iron  body  with  an  extension  which  carries  the 
spring,  a  needle  valve  and  an  atomization  device.  The  body  or 
cage  rests  in  a  bushing,  which  is  pressed  into  the  cylinder  head, 
and  is  held  by  two  studs.  The  needle  valve  a  is  enclosed  along 
the  lower  part,  which  is  in  the  cage,  by  a  bushing  or  barrel  b. 
This  bushing  rests,  at  its  base,  on  the 
atomizer  cone  and  is  prevented  from 
lifting  by  a  coil  spring  at  the .  top. 
As  is  seen  in  Fig.  115  there  is  a 
space,  between  this  bushing  and  the 
cage  wall,  which  serves  as  the  air 
and  fuel  cavity.  The  fuel  charge 
flows  down  the  passage  A  and  enters 
the  fuel  cavity  above  the  atomizer 
disks.  The  disks  are  several  plates 
containing  small  perforations  and 
are  so  placed  as  to  stagger  these  holes. 
The  oil,  by  its  own  weight,  is  forced 
to  pass  through  these  openings  and 
fills  the  intricacies  between  the  plates  FlG- 115-~ Busch-Suizer  type  B 

fuel  valve. 

as  well  as  the  space  around  the  needle 

valve  seat.  The  air  enters  the  cavity  d  above  the  oil 
level.  When  the  needle  valve  is  opened  by  the  valve  rocker, 
the  air,  which  is  at  a  pressure  much  higher  than  that  existing  in 
the  engine  cylinder,  forces  the  oil  charge  into  the  combustion 
space.  The  oil,  as  it  is  broken  up,  passes  from  disk  to  disk,  and 
is  mixed  with  the  air  which  is  flowing  toward  the  cylinder.  The 
emulsion  is  further  increased  as  the  air  and  oil  issues  through  the 
single  small  opening  in  the  atomizer  tip  /.  This  continues  as 
long  as  the  needle  valve  is  open;  this  valve  is  closed  at  the  proper 
time  by  the  fuel  cam,  and  the  small  amount  of  fuel  still  left  in 
the  atomizer  flows  down  around  the  needle  valve  seat.  This 
insures  a  small  charge  of  oil  which  will  enter  the  cylinder  at  the 
next  valve  opening  ahead  of  the  air  and  produce  ignition.  With 
the  usual  fuel  oil  the  fuel  charge  is  able  to  pass  through  the  disks 
under  the  influence  of  its  own  weight.  When  the  valve  opens, 
the  oil  is  forced  into  the  cylinder  in  front  of  the  air.  Since  'this 
oil  is  fairly  light,  it  ignites  even  though  poorly  broken  up.  A 
heavy  oil  behaves  quite  differently.  Its  viscosity  is  such  that 
the  fuel  does  not  readily  flow  through  the  disks  but  rests  above 


136  OIL  ENGINES 

them.  The  air  must  force  the  oil  through  the  atomizer  and,  in 
so  doing,  thoroughly  nebulize  the  charge.  This  type,  then,  has 
the  advantage  of  offering  a  mixing  and  atomizing  effect  in  inverse 
ratio  to  the  gravity  of  the  fuel;  the  actual  degree  of  combustion 
in  the  cylinder  is  fairly  constant,  regardless  of  the  nature  of  the  oil. 
Adjustments — Fuel  Passage. — The  fuel  passage  in  the  body  of 
the  valve  cage  is  equipped  with  an  aluminum  rod  which  stands 
vertically;  the  rod  moves  with  the  vibration  of  the  engine, 
thereby  keeping  the  fuel  line  free  from  stoppage  due  to  dirty  or 
thick  oil.  Even  with  this  precaution,  the  fuel  line  does  collect 
dirt  and  should  be  flushed  out  with  kerosene  on  the  occasion  of 
removal  of  the  valve  and  cage. 

Nozzle  Tip  and  Disks. — The  fuel  cage  tip  has  a  single  central 
perforation  which  gradually  fills  up  with  tarry  deposits,  as  do 
also  the  atomizer  rings  or  disks.  These  can  be  cleaned  with 
kerosene  or  lye  water. 

Needle  Valve. — The  needle  valve  is  of  steel  and  will  corrode 
when  the  fuel  oil  contains  any  acid  or  sulphur.  If  the  cor- 
rosion is  slight,  the  valve  should  be  polished  with  emery  paste 
and,  if  possible,  burnished  with  a  cloth  buffing  wheel.  The 
buffing  of  the  stem  seems  to  retard  the'  rate  of  corrosion.  The 
valve  seat  is  at  an  angle  of  30  degrees  with  the  axis  of  the 
needle  valve.  This  angle,  which  gives  an  angle  of  60  degrees 
to  the  valve  end,  is  such  that  there  is  a  wedging  action  each 
time  the  valve  seats.  This  serves  to  effectually  seal  the  valve 
but  causes  scores  on  the  bearing  surface  in  event  any  grit  has 
settled  on  the  valve. 

Stuffing-box. — The  stuffing-box  has  a  screw  gland  and  is  best 
packed  with  lead  or  babbitt  shavings  or  strings.  This  packing 
conforms  to  the  valve  sufficiently  to  prevent  the  loss  of  air  and 
does  not  become  hard  as  does  all  composition  packing. 

Valve  Spring. — The  valve  spring  is  of  a  length  that  allows  the 
needle  valve  to  be  reground  before  the  initial  compression  of  the 
spring  is  lost.  An  iron  washer  placed  above  the  spring  will  give 
the  effect  of  a  lengthened  stem.  However,  the  valve  cannot  be 
used  after  it  is  worn  short  enough  to  cause  the  spring  plunger 
g  to  drop  below  its  housing. 

Fuel  Line  Check  Valve. — The  fuel  line  has  a  ball  check  valve 
immediately  at  the  valve  cage.  This  ball,  in  time,  wears,  allow- 
ing the  high-pressure  air  to  back  through  the  oil  line  to  the  pump. 
This  causes  the  line  to  become  air  bound. 


FUEL  INJECTION  VALVES  137 

Fuel  Valve  Rocker  Arm. — The  rocker  arm  is  of  two-piece  con- 
struction and  fulcrums  on  an  eccentric  bushing,  which  carries 
the  air-starting  rocker.  The  valve  end  of  the  rocker  has  an 
adjusting  screw  that  can  be  manipulated  to  provide  the  required 
clearance  between  the  roller  and  the  fuel  cam. 

Fuel  Cam. — The  fuel  cam  is  fitted  with  an  adjustable  steel 
nose.  The  nose  is  slotted  and  is  held  by  two  countersunk  screws. 
This  allows  a  considerable  shifting  of  the  nose.  After  the  nose 
is  set  in  position,  it  is  locked  by  end  shims.  These  shims  are 
best  made  of  wrought  iron  and  should  be  hammered  until  the 
entire  recess  is  filled;  the  surface  should  then  be  smoothed  with 
a  file  to  conform  to  the  curvature  of  the  cam. 

Eccentric  Rocker  Bushing. — As  has  been  mentioned,  the  fuel 
rocker  arm  isfulcrumed  on  an  eccentric  bushing,  which  also  carries 
the  starting  rocker.  On  a  four-cylinder  engine  the  two  inside  cyl- 
inders are  fitted  with  starting  valves.  When  the  engine  is  to  be 
started,  the  eccentric  lever  o  of  these  two  cylinders  is  thrown  into 
the  starting  position,  Fig.  82.  This  revolves  the  eccentric  bush- 
ing until  the  fuel  rocker  fails  to  engage  its  cam  while  the  starting 
rocker  comes  into  contact  with  its  cam.  The  levers  of  the  outside 
cylinders  (1  and  4)  are  set  to  " neutral,"  which  disengages  the 
fuel  rocker  and  cam.  As  soon  as  the  air  line  valve  is  opened, 
the  two  starting  cylinders  turn  the  engine  over.  After  one  or 
two  revolutions  of  the  flywheel,  the  levers  of  1  and  4  are  moved 
to  the  running  position,  admitting  fuel  to  the  fuel  valves.  When 
these  cylinders  start  firing,  the  levers  on  No.  2  and  No.  3  cyl- 
inders are  moved  from  the  starting  to  the  running  position, 
cutting  out  the  air-valve  mechanism  and  engaging  the  fuel 
rockers. 

Servomotor. — On  the  larger  Busch-Sulzer  engines  the  timing 
of  the  fuel  injection  is  altered  at  load  changes.  This  is  accom- 
plished through  the  agency  of  a  cylinder  placed  in  front  of  the 
engine,  containing  a  spring  and  piston.  This  cylinder  is  in  com- 
munication with  the  low-pressure  cylinder  of  the  air  compressor. 
The  air-compressor  suction  is  provided  with  a  damper  arrange- 
ment actuated  by  the  engine  governor.  On  low  loads  the  air  to 
the  compressor  is  throttled.  This  results  in  a  lower  discharge 
pressure  in  the  low-pressure  cylinder;  this,  in  turn,  lowers  the 
pressure  existing  in  the  servomotor.  The  spring  then  forces  the 
piston  downward.  The  piston  rod  moves  a  system  of  levers  that 
actuates  an  auxiliary  roller  which  is  linked  to  the  fuel  valve 


138 


OIL  ENGINES 


rocker.  This  layout  appears  in  Fig.  116.  It  will  be  noted  that 
as  the  air  pressure  in  the  servomotor  becomes  lower,  due  to  a 
lighter  load,  the  auxiliary  roller  a  moves  upward,  thereby  allow- 
ing the  cam  nose  to  strike  it  slightly  earlier  in  the  engine  cycle. 
The  auxiliary  roller  is  in  contact  with  the  fuel  rocker  roller  b  at 
all  times,  being  held  by  the  links  c.  The  auxiliary  roller  is  set 
in  such  a  position  that  if  the  injection  opening  is  early,  as  on  low 
load,  this  roller  remains  in  contact  with  the  cam  nose  for  a  smaller 


Hand  Wheel 

FIG.   1 16. — Method  of  altering  full  injections  by  servomotor. 

interval.  Consequently,  on  full  load  the  period  of  injection  be- 
gins later  and  extends  over  a  greater  crank  angle  than  it  does  on 
low  loads.  This  is  shown  in  Fig.  116  where  the  dotted  lines 
indicate  the  roller  positions  on  low  load  and  the  full  lines  are  the 
full-load  positions. 

On  starting  the  engine,  the  handwheel  of  the  servomotor  is 
raised  to  the  half-load  position  while  the  air  from  the  air  compres- 
sor to  the  servomotor  is  cut  off.  This  latter  action  is  for  the 
purpose  of  preventing  the  servomotor  from  moving  the  injection 
roller  to  the  full-load  position.  Frequently,  when  the  engine  is 


FUEL  INJECTION  VALVES 


139 


using  heavy  oil,  it  is  necessary  to  adjust  the  servomotor  hand- 
wheel  to  provide  for  earlier  admission  than  the  air  pressure 
would  give,  or  vice  versa  with  heavy  oil  on  light  loads. 

Fuel  Valve  By-pass. — Each  fuel  line  has  a  by-pass,  or  relief 
valve,  mounted  on  a  block  at  the  camshaft  cover.  Before  the 
engine  is  turned  over  under  air  pressure,  these  valves  should  be 
opened  and  left  in  this  position  until  a  solid  stream  of  oil  issues 
from  each  valve,  thus  indicating  that  all  air  in  the  pump  or  oil 
lines  has  escaped.  When  running,  frequently  one  or  more  cylin- 
ders skip  in  firing,  or  fail  to  fire  at  all;  this,  in  most  cases,  is  due 
to  an  air-bound  fuel  line. 


o.  117.— Mc- 
Intosh  &  Sey- 
mour fuel  valve. 


FIG.  118.- 


-Mclntosh  &  Seymour  stationary  Diesel  fuel 
valve  assembly. 


Mclntosh  &  Seymour  Diesel. — The  fuel  valve  of  this  engine, 
appearing  in  Figs.  117  and  118,  is  contained  in  a  cast-iron  housing 
or  cage.  The  valve,  the  needle  end  of  which  has  a  60-degree 
included  angle,  seats  on  the  cage  itself.  The  upper  end  of  the 
cage  carries  the  spring  housing.  This  end  of  the  valve  stem  is 
screwed  and  locked  into  a  dashpot,  against  which  the  spring 
bears.  The  valve  is  opened  by  the  movement  of  the  rocker  arm 
shown.  The  atomizer  is  the  detail  .of  the  valve  that  differen- 
tiates it  from  other  American  fuel  valves.  This  is  a  gun  metal 


140 


OIL  ENGINES 


barrel,  the  diameters  of  which  are  of  irregular  dimensions.  The 
interior  is  bored  taper,  fitting  the  valve  stem  at  the  upper  end, 
while  a  number  of  passages  connect  this  taper  bore  with  the 
outside  surface.  In  operation  the  charge  of  oil  is  forced,  by  the 
fuel  pump,  through  the  passage  0  and  surrounds  the  atomizer  at 
the  space  /,  issuing  through  the  serrated  fins  at  K  and  L  until 
the  fuel  reaches  the  level  P,  Fig.  119.  The  injection  air  fills  the 
cavity  above  the  atomizer^  and,  when  the  needle  valve  opens, 
this  air  flows  through  the  ports  B  and  along  the  valve  stem  into 


FIG.  119. — Mclntosh  &  Seymour  Diesel  Hesselmann  fuel  valve  action. 

the  cylinder.  The  air  pressure  on  the  surface  of  the  oil  at  J 
remains  constant  while  the  velocity  of  the  air  current  along  the 
valve  stem  reduces  the  pressure  at  the  inner  end  of  the  oil  ports 
E.  The  consequence  is  a  flow  of  oil  through  the  oil  ports  E 
under  the  influence  of  the  unbalanced  air  pressure.  This  oil, 
as  it  enters  the  stream  of  high-velocity  air,  is  broken  up  and 
thoroughly  atomized  by  the  time  it  reaches  the  cylinder  through 
the  atomizer  cap  M .  The  flow  of  oil  continues  until  the  oil  level 
falls  below  the  ports  E.  If  the  fuel  valve  is  properly  timed,  the 
valve  should  then  close,  preventing  an  excessive  amount  of  air 
blowing  into  the  cylinder.  Although  this  excess  air  may  actually 
increase  the  m.e.p.  of  the  engine  as  figured  from  an  indicator 


FUEL  INJECTION  VALVES  141 

card,  it  represents  a  loss  of  power  since  it  has  been  compressed 
to  900  Ibs.  per  sq.  inch  and  is  allowed  to  expand  through  the 
nozzle  to  500  Ibs.  per  sq.  inch  without  doing  any  work. 

On  full  load  the  closure  of  the  needle  valve  should  trap  a 
small  amount  of  oil  immediately  above  the  valve  seat.  This  oil, 
on  the  next  valve  opening,  is  blown  in  ahead  of  the  air  charge, 
providing  an  initial  ignition  to  balance  the  chilling  action  of  the 
expanding  air  charge.  It  is  variously  claimed  that  an  injector 
effect  is  set  up  by  the  air  current.  In  reality,  the  action  is  merely 
that  of  unbalanced  forces,  and  the  oil  below  the  ports  E  remains 
in  the  atomizerT  The  oil,  if  it  contains  dirt  or  a  tarry  base, 
gums  badly  until  the  fuel  chamber  is  filled,  forcing  the  oil  to 
deposit  around  the  valve  stem.  When  this  occurs,  the  oil 
enters  the  cylinder  in  a  slug.  This  is  indicated  by  loss  of  power 
and  a  smoky  exhaust.  The  remedy  is,  of  course,  the  cleansing  of 
the  atomizer. 

It  is  claimed  that  this  valve  design  permits  operation  with  a 
lower  injection  air  pressure  than  with  other  types  of  atomizers. 
In  practice  it  would  appear  that  this  advantage  does  not  exist  ; 
as  at  full  load  a  pressure  of  about  900  Ibs.  gage  is  necessary. 

Adjustments — Valve  Stem. — The  valve  stem,  which  is  steel, 
corrodes  with  a  sulphurized  oil  and  must  be  burnished  at  each  re- 
moval. The  stuffing-box  is  best  packed  with  shredded  babbitt, 
athough  vulcanbestos  is  very  serviceable.  After  the  valve  has  been 
ground,  it  becomes  necessary  to  bring  the  distance  from  the  valve 
tip  to  the  rocker  lock  washer  back  to  the  original  length.  This 
is  accomplished  by  running  both  the  washer  and  lock-nut  up 
until  there  is  the  proper  clearance  between  the  fuel  cam  and  rocker 
roller.  The  spring  tension  can  be  made  normal  by  the  insertion 
of  a  washer  between  the  spring  and  the  dashpot,  or  spring  cap. 
The  valve  can  be  reground  until  the  lock-nut  is  against  the  dash- 
pot  at  which  time  a  new  valve  must  be  secured. 

Valve  Cage. — The  valve  cage  is  held  by  two  studs  and  rests 
on  a  taper  seat  in  the  cylinder  head  casting.  This  taper  joint 
should  be  cleaned  of  soot  before  the  cage  is  replaced  or  the  joint 
will  leak. 

In  removing  the  valve  cage  the  entire  rocker  assembly  of  all 
the  valves  must  be  lifted.  When  only  the  valve  stem  is  removed, 
it  is  merely  necessary  to  unbolt  the  upper  part  of  the  cage  or 
housing  which  contains  the  spring.  The  valve  stem  will  slip 
through  the  fingers  of  the  rocker. 


142 


OIL  ENGINES 


Fuel  Line. — The  fuel  line,  as  on  all  engines,  fills  with  dirt  and 
must  be  flushed  with  kerosene.  There  is  no  by-pass  or  relief 
valve  on  the  fuel  line.  If  the  oil  line  becomes  air-bound,  the 
union  at  the  valve  cage  must  be  unscrewed  to  allow  the  fuel 
line  to  clear.  To  avoid  a  messy  appearance  after  a  line  has  been 
emptied,  a  shallow  pan-  can  be  constructed  to  receive  the  oil. 

Starting  Fuels. — For  starting  purposes, 
it  is  customary  for  the  manufacturer 
to  furnish  a  two-compartment  fuel 
tank,  one  compartment  containing  the 
fuel  oil  which  is  used,  while  kerosene 
is  placed  in  the  other  part.  This  kero- 
sene is  supplied  to  the  engine  in  starting 
since  it  will  ignite  at  a  lower  temperature. 
Mclntosh  &  Seymour  Marine  Diesel 
Fuel  Valve. — The  fuel  valve  of  the 
Mclntosh  &  Seymour  Marine  Engine, 
while  using  a  Hesselman  atomizer,  has 
a  cage  and  actuating  rocker  quite  dif- 
ferent from  that  described  above.  The 
cage  rests  in  a  bushed  opening  in  the 
cylinder  head.  The  rocker  arrange- 
ment is  shown  in  Fig.  120.  The  rocker 
arm,  at  one  end,  is  pinned  to  the 
vertical  push-rod  while  the  other  end 
carries  a  hardened  steel  button  in  con- 
tact with  a  dog  which,  in  turn,  raises  the 
valve  by  its  adjusting  nut.  The  fuel 
cam,  etc.,  have  already  been  discussed 
in  the  preceding  chapter. 

The  Snow  Diesel  Fuel  Valve.— The 
Snow  Diesel  fuel  valve  is  of  the  open 
type  and  is  shown  in  Fig.  121.  The 

valve  is  enclosed  in  a  cast-iron  cage  which  is  held  to  the  cylinder 
head  by  two  studs.  The  cage  extension  carries  the  valve  spring, 
which  seats  on  a  cast-iron  bushing  about  the  valve  stem.  This 
cage  has  a  gasket  at  the  cylinder  head  surface  while  a  ground  joint 
between  the  atomizer  and  head  casting  prevents  water  leakage 
into  the  cylinder.  This  arrangement  provides  an  effective 
water-cooling  of  the  valve  cage  without  the  necessity  of  a  water 
cavity  in  the  cage  body. 


Oil 


FIG.  120.— Mclntosh  & 
Seymour  marine  Diesel  fuel 
injection  valve. 


FUEL.  INJECTION  VALVES 


143 


The  oil  charge  enters  the  valve  cage  at  c,  flowing  along  the 
check  valve  D,  and  comes  to  rest  in  the  small  cup  or  reservoir  E. 
The  air  from  the  compressor  enters  at  B  and  fills  the  recess  at  A. 
At  the  proper  time  the  needle  valve  H  is  opened;  the  air  rushes 
out  the  valve  opening,  through  the  passage  F  and  into  the  cylinder 
at  /.  In  sweeping  over  the  surface  of  the  fuel  charge  at  E,  the 
oil  is  picked  up  and,  as  it  is  forced  along  through  the  atomizer 
disks  C,  is  broken  up. 


FIG.  121. — Snow  Diesel  fuel  valve,  open  type. 

Valve  Stem. — The  valve  stem  can  be  removed,  without  dis- 
turbing the  rocker  arm,  by  unscrewing  it  from  the  spring  bushing. 
In  making  adjustment  for  cam  roller  clearance,  the  stem  is 
screwed  in  or  out  of  this  spring  bushing  as  required.  This  allows 
a  considerable  shortening  of  the  valve  stem,  from  regrinding, 
before  replacement  is  necessary.  The  lower  part  of  the  stem  is 
grooved,  and  these  grooves  collect  dirt  and  consequently  should 
be  cleaned  occasionally. 

Fuel  Check  Valve. — While  cutting  of  the  fuel  valve  seat  due 
to  dirty  oil  is  avoided,  the  scoring  is  merely  transferred  to  the 
check  valve  D.  The  oil  is  at  all  times  in  contact  with  this  valve, 
and  there  is  a  strong  tendency  for  the  dirt  to  settle  on-  th«  inner 
edges  of  the  seat.  This  will  cause  the  valve  to  leak,  although 
the  scoring  action  is  much  less  than  with  the  closed  nozzle 
since  there  is  no  high-velocity  air  stream  present. 

Atomizer  Disks. — The  atomizer  is  provided  with  a  series  of 
fins  about  the  peripheries  of  which  are  a  number  of  notches, 
Fig.  122.  These  notches  will  fill  with  a  tarry  deposit  when  a 
heavy  asphaltum  base  fuel  is  burned.  The  presence  of  these 
deposits  is  usually  indicated  by  the  engine  requiring  a  high  air 


144 


OIL  ENGINES 


injection  pressure  to  maintain  the  correct  speed.     The  atomizer 
disks  should  be  cleaned  at  least  once  a  month — more  often  if  the 


FIG.  122. — Snow  Diesel  atomizer  disc. 


oil  is  dirty.     A  spare  set  can  be  inserted  and  the  old  ones  soaked 
in  lye  water. 


FIG.  123. — Kerting  Diesel  fuel  valve,  open  type. 

Korting  Diesel  Fuel  Valve.— A  fuel  valve  along  the  same  lines 
has  been  manufactured  by  the  Korting  Co.  for  some'  years. 
This  valve,  however,  has  no  atomizer  disks.  The  oil  is  swept 


FUEL  INJECTION  VALVES 


145 


into  the  cylinder  by  the  passage  of  the  air  over  the  surface  of 
the  oil  pool.     This  valve  appears  in  Fig.  123. 

The  McEwen  Diesel  Fuel  Valve. — Another  design  of  open- 
type  fuel  valve  is  found  on  the  McEwen  Diesel.  As  outlined 
in  Fig.  124,  this  valve  consists  of  a  cast-iron  housing,  or  cage, 
which  is  bolted  to  the  cylinder  head  with  the  axis  of  the  fuel 
nozzle  coincident  with  the  axis  of  the  cylinder,  and  of  the  neces- 
sary atomizer  and  needle  valve. 


FIG.  124. — Fuel  injection   valve,  McEwen  Diesel. 

The  fuel  oil  enters  the  valve  at  a  and,  passing  around  the 
ball  check,  deposits  in  the  fuel  chamber  6;  part  of  the  charge 
also  flows  into  the  fuel  valve  plug.  The  air  charge  enters  at  c 
and  surrounds  the  base  of  the  valve  stem  at  d.  When  the  needle 
valve  opens,  the  air  passes  through  the  valve  opening  and  into 
the  air  port  e\  a  part  also  completely  fills  the  fuel  valve  nut 
cavity  where  it  exerts  a  pressure  on  the  oil  contained  in  the 
reservoir  b.  The  air  flowing  through  the  port  e  toward  the  cyl- 
inder attains  a  high  velocity  with  a  decrease  in  pressure.  The 
air  above  the  oil,  having  a  fairly  large  volume,  maintains  its 
original  pressure.  This  unbalanced  pressure  produces  a  flow  of 
oil  in  the  port  F.  This  oil,  after  passing  through  the  small  chan- 
nels G,  encounters  the  stream  of  high-velocity  air  and  is  swept 
10 


146 


OIL  ENGINES 


into  the  cylinder.  The  oil  issues  from  the  channels  G  in  very  fine 
streams,  which  are  quickly  mixed  with  the  air.  The  atomiza- 
tion  is  further  increased  by  the  action  of  the  atomizating  plate  H. 
This  valve  is  one  of  the  best  yet  designed.  The  air  does  not 
"slug "  the  oil,  causing  a  poor  atomizing  effect.  On  the  contrary, 
the  channels  G  afe  of  such  cross-section  that  the  oil  issues  from 
them  in  streams  of  a  size  that  will  allow  a  thorough  breaking-up 
by  the  air.  Regardless  of  the  engine  load  and  the  volume  of 
the  fuel  charge,  the  rate  of  fuel  injection  into  the  cylinder  is 
fairly  constant  with  any  given  fuel.  Even  a  decrease  of  100  Ibs. 
in  the  injection  air  pressure  apparently  has  but  minor  effect  on 
the  degree  of  atomization.  Oils  of  different  characteristics  do 


FIG.  125. — McEwen  Diesel  fuel  valve,  open  type.     Early  model. 

not  flow  through  the  passages  at  identical  rates.  The  natural 
consequence  is  a  variable  rate  of  fuel  injection  unless  disks  with 
different  size  passages  are  employed.  A  partial  remedy  lies 
in  the  control  of  the  injection  air  pressure.  Figure  125  is  an 
early  model  used  on  the  McEwen  engine.  It  differs  but  slightly 
from  Fig.  124. 

Adjustments. — The  ball  check  valve  requires  some  attention; 
especially  is  this  true  with  dirty  oils.  In  case  the  seat  is  worn, 
a  new  contact  can  be  formed  by  using  a  hardwood  stick  or 
soft  copper  pin;  lightly  striking  the  pin  will  cause  the  ball  to 
renew  the  curvature  of  the  valve  cage  seat. 

The  roller,  actuating  the  valve,  is  mounted  on  an  eccentric. 
A  lever  moves  the  roller  into  and  out  of  contact  with  the  fuel 
cam.  In  changing  the  valve  timing,  the  rocker  roller  can  be 
moved  by  means  of  the  adjusting  pin.  The  adjusting  pin 
passes  through  the  roller  pin  or  bearing  and  moves  the  bearing 
along  the  slots  shown.  The  fuel  valve  rocker  set-screw,  resting 
on  the  end  of  the  valve  stem,  controls  the  clearance  between 
stem  and  rocker. 


FUEL  INJECTION  VALVES 


147 


Allis-Chalmers  Diesel  Fuel  Valve. — The  fuel  valve  of  this 
engine  is  of  the  open  type,  Fig.  126.  The  body  is  a  steel  block, 
the  nozzle  extension  of  which  fits  into  the  cylinder  head.  The  oil 
enters  the  valve  body  at  the  bottom,  the  line  having  two  poppet 
check  valves.  The  air  enters  the  block  at  the  top  and  fills  a 
recess  behind  the  fuel  valve.  As  the  lever  or  rocker  arm  lifts 
the  valve,  the  air  rushes  through  the  valve  opening  and  flows 
into  the  oil  cavity  at  the  point  a.  As  it  passes  over  the  body  of 


FIG.   126. — Allis-Chalmers  Diesel  fuel  valve. 


fuel,  the  air  picks  up  the  oil  and  blows  it  into  the  cylinder.  The 
velocity  of  the  air  stream,  together  with  the  action  of  the  atomizer, 
breaks  up  the  charge  into  particles.  The  nozzle  tip  is  flaring 
in  contour,  causing  the  mixture  of  air  and  oil  to  assume  a  cone 
shape. 

Adjustments.  Check  Valves. — The  oil  check  valves  require 
regrinding  at  intervals,  especially  with  dirty  oils.  The  check 
valve  cage  is  quite  easily  removed  for  valve  repairs  by  un- 
shipping the  oil  pipe  line  and  unscrewing  the  cage  from  the  fuel 
valve  body. 


148 


OIL  ENGINES 


Needle  Valve. — The  valve  is  of  generous  dimensions,  and 
consequently  very  little  regrinding  is  necessary. 

The  Atomizer  Tip. — The  atomizer,  since  it  is  exposed  to  the 
cylinder  temperature,  carbonizes  or  gums  from  the  small  amount 
of  oil  that  adheres  to  the  atomizer  after  the  air  blast  ceases. 
A  spare  tip  should  be  on  hand  at  all  times.  The  presence  of 
deposits  will  ordinarily  be  indicated  by  the  engine  laboring 
until  the  injection  air  pressure  is  raised. 

Fuel  Cam. — The  layshaft  is  provided  with  a  hub  disk  which  is 
held  by  a  nose-key.  This  hub  is  fitted  with  an  extension  upon 


Hub  Disc 


Fuel  Cam 


FIG.   127. — Allis-Chalmers  Diesel  fuel  cam. 


which  is  keyed  the  air-starting  cam.  The  hub  flange,  as  will 
be  observed  in  Fig.  127,  is  slotted.  Into  these  slots  are  placed 
the  fuel  cam  bolts.  The  fuel  cam  also  appears  in  Fig.  126, 
where  it  can  be  seen  that  it  has  an  adjustable  nose.  In  set- 
ting the  fuel  valve  timing,  the  fuel  cam  can  be  moved  several 
degrees  around  the  hub  disks  and  held  in  place  by  the  bolts. 
This  provides  the  easiest  method  of  adjusting  the  fuel  valve 
timing. 


FUEL  INJECTION  VALVES 


149 


The  National  Transit  Diesel  Fuel  Valve. —  The  National 
Transit  Co.  equip  their  Diesels  with  an  open-nozzle  fuel  valve, 
Fig.  128.  The  needle  valve  is  placed  vertically  in  the  valve 
block  and  has  the  closing  spring  located  in  the  top  of  the 
valve  body.  This  spring  is  enclosed  in  a  sleeve  which  is  in 


FIG.  128.— National  Transit  1918  design  Diesel  fuel  valve  and  cam  assembly. 

contact  with  the  needle  valve  and  is  moved  vertically,  compress- 
ing the  spring,  as  the  valve  is  opened  by  the  rocker.  The  oil 
enters  the  valve  passage  of  the  atomizer  through  the  check  valve  a. 
The  oil  reservoir  extends  the  depth  of  the  cylinder  head.  This 
causes  the  oil  charge  to  spread  out  in  a  thin  sheet;  consequently, 
the  air  does  not  pick  up  the  oil  in  slugs.  Owing  to"  this  passage 
length,  no  atomizer  disks  are  necessary. 


150  OIL  ENGINES 

The  valve  body  has  no  cooling  water  passages  since  it  rests 
in  a  thin  bushing  pressed  into  the  cylinder  head;  the  cooling  effect 
through  the  bushing  is  quite  satisfactory. 

The  fuel  valve  of  the  National  Transit  Diesel  manufactured 
prior  to  1918  was  opened  by  a  push-rod  carried  in  the  hollow 
housing  of  the  camshaft  end  bearing.  This  push-rod  is  in  con- 
tact with  the  fuel  cam,  Fig.  13,  Chapter  II. 

On  later  Diesels  the  fuel  valves  are  driven  from  the  camshaft 
in  front  of  the  cylinder,  as  appears  in  Fig.  128.  The  fuel  valve 
and  starting  valve  rocker  are  here  mounted  on  an  eccentric  which 
is  machined  on  the  fulcrum  shaft.  In  starting,  a  lever  gives  an 
angular  displacement  to  the  fulcrum  shaft;  this  shifts  the  eccen- 
tric, throwing  the  fuel  valve  rocker  away  from  the  valve  stem 
and  moving  the  air  starter  rocker  into  position. 

Fuel  Valve  Timing. — In  timing  the  valve  opening  and  closure 
the  adjusting  nut  on  the  valve  stem  is  set  to  contact  with  the 
fuel  cam  at  the  desired  piston  angle  for  valve  opening,  as  with 
practically  all  engines.  The  cam  nose  can  be  shifted  to  give 
the  required  closure.  The  spring  cap  must  be  in  contact  with 
the  needle  valve  body  at  all  times.  After  the  valve  is  reground 
a  few  times  the  cap,  or  bushing,  fails  to  touch  the  valve.  To 
overcome  this  trouble  the  bushing  should  be  ground  off  at  the 
surface  where  it  seats  on  the  valve  body  at  B.  This  has  the  effect 
of  lowering  the  cap,  causing  it  to  again  touch  the  valve. 

Standard  Fuel  Oil  Engine  Fuel  Valve.— The  fuel  valve  of 
this  engine  is  of  the  open-nozzle  .type.  The  valve  is  housed  in  a 
cast-iron  bracket  block  and  consists,  in  the  main,  of  the  steel  valve 
body,  atomizer,  needle  valve,  fuel  check  valve,  and  valve  actu- 
ating spring  and  rocker,  Fig.  129. 

The  operation  is  as  follows:  The  charge  of  fuel,  flowing 
through  the  pipe  a  and  the  check  valve,  enters  the  atomizer 
through  the  small  port  holes  B.  The  air  enters  at  the  side  of 
the  valve  block,  passing  around  the  valve  stem  above  the  seat 
at  C.  As  the  needle  valve  is  raised,  this  air  enters  the  atomizer 
passage  D;  to  do  this,  the  air  must  pass  through  the  atomizer 
cone  shown  in  the  section  B-B.  This  effectually  breaks  up  the 
air  stream,  preventing  the  air  from  " slugging"  the  oil  into  the 
cylinder.  As  the  high-velocity  air  passes  over  the  oil,  the  latter 
is  picked  up  and  swept  into  the  cylinder.  As  a  means  of  giving 
sensitive  control  of  the  fuel  supply  on  low  loads  and  of  eliminating 
" hunting"  by  the  governor,  a  by-pass  fuel  valve  is  placed  in_the 


FUEL  INJECTION  VALVES 


151 


fuel  line.     When  low  loads  are  carried,  the  governor,  which  is 
of  the  Rites  Interia  type,  is  at  the  extreme  limit  of  its  travel. 


Ytater  Fuel  OilSupplu 

Outlet.  I 


Section  A- A 


'B 

Section  X~X 

FIG.   129. — Standard  Fuel  Oil  two-cycle  Diesel  fuel  valve. 

In  this  condition  this  type  of  governor  is  unstable  and  will  hunt 
excessively.  By  cracking  the  overflow  valve  to  allow  part  of 
the  fuel  pumped  to  by-pass  back  to 
the  tank,  the  governor  is  compelled  to 
handle  more  than  the  engine's  require- 
ments. The  governor  then  moves 
outward  to  a  more  stable  position, 
giving  a  closer  regulation  to  the  engine 
speed. 

Fuel  Valve  Actuating  Mechanism.— 
The  fuel  valve  is  operated  by  a  unique 
cam    arrangement    radically    different 
from    that    used     on    all    other 
Diesels.     The  device  appears  in 
Fig.  130  where  a,  the  fuel  valve, 
is  moved  by  the  dog  6;  this  dog, 
in  turn,  receives  its  motion  from 
the  cam  lever  d.     On  w     Crml( 
the  lower  end  of  this 
lever    is     mounted    a 
roller  which  is  in  con-  FlG>  130' 

tact    with    the    cam    e.      It    will    be  observed    that,    as    the 
engine    turns   over,    the  drag   crank,    being    connected  ^to  the 


152 


OIL  ENGINES 


reach-rod  and  crank  /,  will  raise  the  needle  valve  through 
this  system  of  levers.  The  cam  nose  comes  under  the 
roller  twice  in  each  revolution  of  the  engine,  and,  since  the 
engine  is  a  two-stroke-cycle,  it  then  becomes  necessary  to  pro- 


Developed  Surface  of  Cam 
Showing  Roller  in  the  Two  Extreme  End  Positions 


I 
FIG.   131. — Standard   Fuel  Oil  engine  fuel  cam. 

vide  some  means  whereby  the  roller  is  raised  only  once  per 
revolution  of  the  engine  shaft.  This  is  accomplished  by  equip- 
ping the  cam  roller  with  two  flanges,  as  more  fully  illustrated  in 
Fig.  131.  The  cam  is  milled  with  curved  sides,  and  the  nose 


FUEL  INJECTION  VALVES  153 

extends  over  only  one-half  of  the  cam  width.  As  the  reach-rod 
moves  to  the1  left,  Fig.  131,  the  right-hand  roller  flange  bears 
against  the  cam  edge;  the  cam  nose  then  passes  between  the 
flange  and  the  roller.  At  the  extreme  travel  of  the  reach-rod, 
the  curved  side  of  the  cam  throws  the  roller  to  the  left,  pulling 
it  into  the  position  a,  Fig.  131.  When  the  drag  crank  reverses 
the  travel  of  the  reach-rod  /,  the  cam  nose  strikes  the  roller, 
raising  the  needle  valve;  the  cam  at  the  end  of  its  travel  then 
shifts  the  roller  to  the  right  to  the  position  b,  which  allows  the 
roller  on  the  return  stroke  to  slide  over  the  cam,  untouched  by 
the  nose. 

Adjustments.  Timing  of  Fuel  Valve. — The  point  of  be- 
ginning of  fuel  injection  can  be  altered  by  adjusting  the  reach- 
rod  length.  The  clearance  between  the  valve  spring  cap  and 
dog  is  controlled  by  the  adjusting  set-screw  on  the  roller  lever  d; 
this  need  not  be  more  than  3^2-inch. 

Fuel  Valve. — The  valve  body  is  water-cooled,  and  it  is  neces- 
sary to  use  this  cooling  system  when  high-gravity  fuel  oil  is 
burned.  With  heavy  oils,  around  24°  Baume,  the  water  tends 
to  chill  the  valve  and  lower  its  atomizing  efficiency;  the  result 
is  a  decidedly  smoky  exhaust.  It  is  advisable,  with  such  oils,  to 
discontinue  the  flow  of  water  around  the  valve. 

Needle  Valve. — The  valve  seat  requires  the  same  attention  as 
do  all  open-type  valves.  The  shortening  of  the  valve,  due  to 
regrinding,  can  be  compensated  for  by  screwing  the  valve  out  of 
the  spring  cap  or  dash-pot. 

Fuel  Check  Valve. — Especial  attention  should  be  given  to 
the  fuel  check  valve  while  the  plant  is  burning  dirty  oil.  If  the 
fuel  be  sulphurized  to  any  extent,  this  valve  will  corrode  and  of 
course  demand  regrinding.  Since  the  fuel  is  deposited  in  the 
atomizer  during  the  compression  stroke,  the  check  works  against 
a  considerable  pressure — from  250  to  400  Ibs. ;  the  sudden  opening 
and  closing  of  the  valve  in  time  hammer  the  seat.  The  check 
valve  stem  must  be  kept  clean  from  corrosion  since  the  spring 
is  light  and  will  not  close  the  valve  against. any  decided  binding 
of  the  stem. 

Injection  Air. — The  injection  air  pressure  is  controlled  by  a 
governor-controlled  valve,  interposed  between  the  low-  and 
high-pressure  air  compressor  cylinders.  This  is  illustrated  in 
Fig.  161. 


154 


OIL  ENGINES 


Fulton  Machine  Co.  Marine  Diesel  Fuel  Valve. — Figure  132 
illustrates  the  fuel  valve  of  the  Fulton  Marine  Diesel.  It  is  along 
standard  practice  in  closed-nozzle  valves  and  is  controlled  by  a 
rocker  from  the  camshaft. 

Nelseco  Marine  Diesel  Fuel  Valve. — This 
Diesel  employs  a  closed-nozzle  valve.  The 
valve  is  located  vertically  in  the  cylinder 
head  and  is  actuated  by  a  rocker  arrangement 
shown  in  Figs.  19  and  103. 

Fuel  Valves  for  Tar  Oil.— Figures  133  and 
134  illustrate  fuel  valves  designed  to  use  tar 
oil  as  the  main  charge  and  light  oil  for 
primary  ignition. 

Regrinding  Fuel  Valves. — Regardless  of 
the  type  of  fuel  valve,  each,  sooner  or  later, 
FIG.  132.— Fulton  requires  regrinding.  In  performing  this  pro- 
Machine  Co.  Diesel  cess,  an  engineer  should  be  very  miserly  with 
the  amount  of  grinding  paste  used.  The  best 
compound  is  one  of  powdered  glass  and  vaseline,  or  emery  flour 
and  vaseline.  Only  a  very  small  amount  should  be  placed  on 
the  needle,  being  spread  out  evenly  over  the  entire  seating 
surface.  The  entire  valve,  with  the  exception  of  the  spring, 
should  be  assembled  when  grinding.  This  is  to  insure  that  the 


FIG.  133. — Korting  tar  oil  fuel  valve. 

valve  is  aligned  properly.  It  is  unnecessary  to  secure  more 
than  a  thin  line  contact  at  the  seat — ^4  inch  in  width  is  ample. 
After  grinding,  it  is  advisable  to  disassemble  the  entire  valve  and 
cage  and  wash  very  thoroughly  with  kerosene.  This  is  to 
remove  all  emery  particles. 

New   Needle  Valves. — Undoubtedly  the  average  plant  can 
profitably  purchase  new  needle  valves  from  the  engine  builder. 


FUEL  INJECTION  VALVES 


155 


Where  a  plant  contains  several  engines,  this  valve  cost  is  of  some 
moment.  Perfectly  good  valves  can  be  made  of  drill  rod  or  cold 
rolled  steel  with  either  a  tool-steel  or  phosphor-bronze  tip. 


FIG.   134.— Tar  oil  fuel  valve. 


Lubrication  of  Valve  Stem. — The  valve  stem  gradually  be- 
comes coated  with  a  thin  layer  of  oil  residue,  this  being  more 
noticeable  in  non-cooled  valves.  To  prevent  binding  of  the  stem, 
it  should  be  constantly  lubricated.  A  small  amount  of  kerosene 
injected  around  the  valve  at  least  once  every  twenty-four  hours 
will  remove  any  residue. 

Leaky  Fuel  Valves. — A  leaky  injection  valve  usually  betrays 
its  presence  by  causing  the  engine  exhaust  to  be  smoky.  Leaky 


156  OIL  ENGINES 

valves  also  allow  the  fuel  charge  to  seep  into  the  cylinder  during 
the  compression  stroke  and  so  produce  violent  preignition. 

Incorrect  Fuel  Valve  Timing. — If  the  valve  opens  too  early,  a 
sharp  metallic  click  or  pound  will  be  heard  in  the  cylinder.  This 
is  evidence  of  premature  combustion.  If  the  valve  opens  late,  a 
dull  thump  or  pound,  quite  like  a  pound  due  to  loose  pin  bearing, 
can  be  heard.  Furthermore,  a  smoky  exhaust  ordinarily  ac- 
companies this  pounding. 

Clogged  Atomizer  or  Nozzle -tip  Disk. — When  either  the 
atomizer  or  the  disk  at  the  end  of  the  fuel  valve,  sometimes 
called  the  burner  plate,  is  clogged,  the  exhaust  is  smoky. 

Sticking  Valve  Stem. — When  the  fuel  valve  stem  sticks  in 
the  open  position,  the  exhaust  will  be  smoky  and  the  injection 
air  gage  will  show  a  drop — with  the  open  nozzle,  the  gage  needle 
will  show  as  much  as  a  75  per  cent,  pressure  drop. 

Fuel  Valve  Cooling  Jacket  Temperature. — The  desirable  tem- 
perature, at  which  the  discharge  line  from  the  fuel  valve  water 
jacket  should  be  carried,  depends  on  the  .characteristics  of  the 
fuels.  If  the  oil  is  heavy  and  viscous,  the  discharge  should  be 
around  160°  Fahrenheit.  With  fuel  oil  of  28°  Baume*.  and 
higher,  120°  Fahrenheit  is  amply  high  since  the  valve  must  be 
cool  to  prevent  gassing  of  the  light  oil. 

Adjustable  Injection  Air  Pressure. — The  engineer  can  appre- 
ciate the  necessity  of  having  a  higher  injection  air  pressure  when 
the  engine  is  carrying  full  load  than  when  under  a  light  load. 
When  the  fuel  charge  delivered  to  the  fuel  valve  is  large,  as  on  full 
load,  the  resistance  or  "  braking "  action  of  the  atomizer  is  high 
and  requires  a  high  pressure  to  force  the  entire  charge  of  oil  into 
the  cylinder.  On  light  loads,  the  oil  occupies  only  part  of  the 
atomizing  space,  and  consequently  a  light  air  pressure  is  suffi- 
cient. If  the  pressure  is  high  on  light  loads,  the  oil  is  blown  into 
the  cylinder  at  an  increased  rate.  The  passage  of  the  fuel 
would  then  require  only  part  of  the  time  during  which  the  needle 
valve  is  opened.  The  remainder  of  the  period  of  valve  opening 
would  be  devoted  to  the  passage  of  pure  air.  The  high  velocity 
of  the  free  air  as  it  left  the  nozzle  tip  would  chill  the  tip  and  lower 
the  entire  cylinder  temperature,  causing  a  decreased  cylinder 
efficiency  as  well  as  a  direct  loss  of  air  that  has  been  compressed 
at  a  considerable  expense  of  power.  Furthermore,  if  the  air 
pressure  is  high  on  low  loads,  a  sharp  knock  is  produced  in  the 
cylinder  which  results  from  the  inrush  of  air  at  a  pressure  far 


FUEL  INJECTION  VALVES  157 

above  cylinder  pressure.  Conversely,  if  the  air  pressure  is  too 
low  the  engine  will  smoke  since  the  fuel  has  not  been  sufficiently 
atomized. 

It  is  necessary  for  the  successful  operation  of  any  Diesel  that 
the  injection  air  pressure  be  altered  to  conform  to  load  change. 
This  adjustment  can  be  under  manual  control  of  the  engineer, 
as  is  the  general  practice.  The  manual  control  can  be  obtained  in 
several  ways.  The  Mclntosh  &  Seymour  Marine  Engine  is  pro- 
vided with  a  clearance  chamber  on  the  low-pressure  cylinder, 
whose  volume  can  be  altered,  changing  the  air  discharge  pressure. 
Other  builders  arrange  for  the  operator  to  adjust  the  low-pressure 
suction,  obtaining  the  required  air-pressure  control.  However, 
on  fluctuating  loads,  this  entails  constant  attention  and  is  more 
suitably  handled  by  some  automatic  arrangement.  There  are 
several  designs  of  automatic  injection  control.  The  Busch- 
Sulzer  Diesel  throttles  the  compressor  suction  through  a  linkage 
from  the  engine  governor.  The  Standard  Fuel  Oil  Engines,  as 
has  been  outlined,  use  a  governor-controlled  air  by-pass  valve. 
These  varied  control  arrangements  will  be  taken  up  in  the  dis- 
cussion on  air  compressors. 

Adjustable  Fuel  Valve  Timing. — The  usual  Diesel  engine 
fuel  valve  is  designed  with  a  constant  period  of  valve  opening, 
regardless  of  load  conditions.  In  the  Otto-type  explosive 
engine  the  efficiency  of  the  engine  depends  on  the  maximum 
explosive  pressure.  With  the  Diesel  engine  the  efficiency 
depends  both  on  the  combustion  pressure,  which  should  be 
identical  with  the  maximum  compression  pressure,  and  on  the 
duration  of  the  fuel  injection.  It  is  very  clear  that  with  load 
changes  the  time  during  which  the  fuel  is  injected  should 
also  vary.  Since  the  rate  of  combustion  should  be  constant, 
the  period  of  injection  must  vary  if  the  greatest  possible  effi- 
ciency is  to  be  secured.  Furthermore,  a  factor  of  operation  also 
enters  into  the  problem.  On  low  loads  the  amount  of  oil  is 
small  and  will  be  entirely  blown  into  the  cylinder  long  before 
the  valve  closes.  The  balance  of  the  valve  opening  period 
is  taken  up  with  the  injection  of  high-pressure  injection  air. 
This  air  assists  in  no  way  toward  the  combustion.  For  these 
reasons  several  European  builders,  as  well  as  the  Busch-Sulzer 
Co.,  have  adopted  a  form  of  injection  timing  control  along  the 
lines  of  the  servomotor  in  Fig.  116. 


158  OIL  ENGINES 

Timing  of  Fuel  Valves/ — In  timing  a  fuel  valve  the  engine 
is  pinched  over  until  it  is  several  degrees  ahead  of  the  desired 
point  of  fuel  valve  opening.  The  air  line  valve  is  "  cracked," 
giving  about  75  Ibs.  air  pressure  on  the  fuel  valve.  The  indi- 
cator plug  is  removed,  and  the  engine  is  slowly  barred  over 
until  the  trammel  cuts  the  opening  mark  on  the  flywheel.  The 
injection  valve  should  now  start  to  open,  as  evidenced  by  the 
sound  of  injection  air  blowing  into  the  cylinder.  If  the  valve 
opens  before  the  mark  is  reached,  the  rocker  clearance  can 
be  increased,  producing  a  later  opening.  If  the  valve  opens 
late,  the  clearance  can  be  reduced.  The  engine  should  be 
barred  on  to  the  closing  mark,  and  the  sound  of  the  escaping 
air  should  cease  as  the  mark  is  reached.  Since  the  roller  clear- 
ance has  been  altered  to  make  the  opening  earlier,  the  closing 
point  will  probably  be  late.  It  then  becomes  necessary  to  turn 
the  engine  back  ahead  of  the  valve  opening  mark  and  shift 
the  cam  nose.  The  nose  should  be  shifted  to  produce  the  re- 
quired opening  with  the  roller  clearance  correct.  Then,  on 
checking  the  closing  point,  it  should  either  be  correct  or  early. 
If  the  latter,  the  nose  must  be  shifted  back  a  trifle  and  the  roller 
clearance  made  less.  This  should  produce  the  required  opening 
and  closure.  If  the  nose  is  excessively  worn,  it  is  impossible  to 
obtain  a  correct  timing,  and  a  new  nose  must  be  secured. 

Back  Lash. — The  camshaft  gears  are  not  immune  to  wear, 
and  in  the  course  of  five  to  seven  years  of  constant  service  the 
back  lash  between  the  gears  becomes  noticeable.  The  clear- 
ance between  the  gear  teeth  has  a  very  detrimental  effect  on  the 
injection  cam.  As  the  cam  nose  contacts  with  the  valve  rocker 
roller,  the  pressure  that  the  spring  offers  against  the  rocker 
movement  is  considerable.  As  the  roller  travels  over  the  sur- 
face of  the  cam  nose  and  starts  down  along  the  back  slope,  this 
spring  pressure  forces  the  camshaft  forward,  causing  the  valve 
to  close  early.  Since  the  wear  is  between  the  teeth,  the  camshaft 
is  already  behind  its  exact  timing  with  the  engine  shaft,  and 
consequently  the  opening  of  the  fuel  valve  is  late  and  the  closure 
is  early.  A  new  cam  nose  of  greater  length  will  partially  over- 
come the  defect,  but  new  gears  should  be  ordered  to  replace  the 
worn  ones. 


CHAPTER  X 
FUEL  PUMPS 

TYPES.     ADJUSTMENTS 

Fuel  Pumps. — While  adjustments  of  a  Diesel  fuel  pump  are 
not  of  frequent  occurrence,  nevertheless,  this  particular  part 
of  the  engine  is  of  vital  importance.  The  successful  operation 
of  a  Diesel  depends,  in  a  great  measure,  upon  the  accuracy  and 
reliability  of  the  pumping  mechanism.  When  it  is  considered 
that  on  a  100  h.p.  cylinder,  operating  at  200  r.p.m.  or  100 
power  strokes  per  minute,  the  volume  of  a  single  full-load  fuel 
charge  is  less  than  .3  cubic  inch,  the  necessity  of  accurate 
pumping  is  apparent.  Since  the  usual  speed  regulation  require- 
ment is  2  per  cent,  on  each  side  of  normal,  the  extreme  variation 
that  is  permissible  in  the  volume  of  a  single  injection  at  a  given 
speed  is  .006  cubic  inch.  The  pump,  then,  must  be  not  only 
correct  in  design  but  also  absolutely  high-grade  in  the  workman- 
ship involved  in  its  actual  manufacture. 

As  has  been  previously  outlined,  two  types  of  fuel  injection 
are  in  use:  the  open-  and  the  enclosed-nozzle  type.  The 
fuel  pumps  follow  the  same  classification.  First,  the  pumps 
on  engines  employing  the  closed-nozzle  fuel  valve  must  be 
constructed  to  resist  a  pumping  head  equivalent  of  more  than 
1000  Ibs.  per  sq.  inch.  This  demands  rugged  construction  and 
absolutely  leak-proof  pump  valves.  The  governor  control, 
where  the  control  is  through  the  pump  plunger,  is  called  upon 
to  withstand  severe  stresses.  The  open-nozzle  fuel  valve  offers 
no  pressure  resistance  to  the  pump  discharge;  consequently  the 
pumping  head  consists  of  merely  the  pipe  and  check  valve 
resistances,  which  are  negligible.  This  fact  enables  the  fuel 
pump  to  be  designed  with  direct  control  of  the  pump  plunger, 
with  but  slight  reactions  on  the  governor. 

American  Diesel. — The  numerous  American  engines  that  are 
still  in  service  are  equipped  with  the  Bagtrup  governor  and  fuel 
pump,  appearing  in  Fig.  135.  The  mechanism  consists  of  a 
pump  body  in  which  reciprocates  the  plunger,  one  plunger  for 

.159 


160 


OIL  ENGINES 


each  engine  cylinder,  the  plunger  being  driven  by  an  eccentric 
mounted  on  the  pump  shaft.  This  shaft  carries  a  gear  which  is 
actuated  by  a  train  of  gears  from  the  engine  crankshaft.  The 

suction  valve  is  mechanically  oper- 
ated, by  means  of  a  bell-crank  B 
and  reach-rod  A,  from  the  plunger 
eccentric  strap.  The  bell-crank 
fulcrums  on  an  eccentric  shaft  C 
controlled  by  the  governor  sleeve. 
The  suction  valve  is  opened  during 
the  suction  stroke  and  part  of  the 
discharge  stroke.  If  the  load  is 
heavy  the  fulcrum  pivot  is  raised, 
allowing  the  suction  valve  to  close 
I  early;  the  fuel  then  is  forced  out 
through  the  discharge  valve  into 
the  fuel  injection  valve.  On  light 
loads  the  governor  lowers  the 
fulcrum,  causing  the  suction  valve 
to  remain  open  for  a  greater  part 
of  the  plunger  stroke;  the  oil  then 
passes  back  through  the  suction 
valve. 

The  reaction  of  the  governor 
sleeve  is  heavy,  and  the  speed 
regulation  is  not  as  close  as  is  de- 
manded in  electric  plants.  In 
starting  the  engine  a  hand  crank 
is  provided,  which  allows  the  fuel 
line  and  injection  valve  to  be 
charged  before  the  engine  is  turned 
over. 

Adjustments.  Setting  Suction 
Valve. — In  setting  the  suction 
valve  the  governor  should  be 
blocked  to  the  mid-position  and 
the  particular  pump  plunger  placed  on  the  upper  dead-center. 
The  suction  valve  lever  should  then  clear  the  suction  valve  stem 
by  ^32  inch.  This  clearance  can  be  secured  by  altering  the 
length  of  the  lever  reach-rod  A,  which  has  turnbuckle  ends. 


FIG. 


135. — American   Diesel   fuel 
pump. 


FUEL  PUMPS  161 

Leaky  Valves. — The  suction  valve,  being  of  the  poppet  type, 
frequently  leaks.  The  proper  method  of  regrinding  is  to  remove 
the  valve  and  cage.  Disassembling,  the  spring  is  removed  and 
the  valve  coated  with  emery  flour  and  vaseline  and  again  placed 
in  the  cage.  A  nail  thrust  through  the  cotter  opening  makes  a 
convenient  handle  with  which  to  turn  the  valve. 

Discharge  Valves. — The  discharge  line  has  two  ball  valves. 
When  the  oil  is  clean  and  free  from  dirt,  little  trouble  is  ex- 
perienced. The  chief  attention  is  given  to  the  valve  seats. 
These  seats  tend  to  wear  rounded,  making  a  poor  seal.  When 
the  seat  is  in  this  condition,  it  should  be  reamed  to  the  correct 
45-degree  angle;  in  this  work  the  reamer  must  not  chatter,  or 
the  seat  will  not  be  oil-tight.  The  lift  of  the  valve  should  not 
exceed  }{$  inch.  If  it  is  greater,  the  ball  valve  will  be  slow  in 
seating  and  will  allow  part  of  the  oil  to  flow  back  through  the 
valve  opening.  With  heavy  oils  the  seating  is  so  slow  that  a 
small  helical  spring  becomes  necessary. 

Levers  and  Pins. — On  these  old  engines  the  pump  levers  and 
pins  are  generally  badly  worn.  An  engineer,  when  this  condition 
exists,  should  promptly  ream  the  pin  bearings  to  a  larger  diameter 
and  turn  up  new  pins  to  conform.  For  this  work  an  expansion 
reamer  is  desirable  in  order  to  handle  all  the  various  size  pin 
bearings. 

Busch-Sulzer  Type  B  Diesel  Fuel  Pump. — While  the  mechan- 
ical details  differ,  the  Busch-Sulzer  Type  B  Diesel's  fuel  pump 
follows  the  same  principle  as  does  the  American  engine  just  dis- 
cussed. Figure  136  is  a  cross-section  of  the  Type  B  pump,  show- 
ing one  plunger.  This  is  along  designs  adopted  by  the  majority 
of  European  and  English  Diesel  builders.  In  this  construction 
the  plunger  A  is  driven  by  an  eccentric  B  keyed  to  the  vertical 
governor  shaft  C.  The  suction  valve  is  mechanically  operated 
by  a  dog  F,  which  swings  on  an  eccentric  G.  This  eccentric  is 
mounted  on  a  small  shaft  controlled  by  the  governor  K  through 
a  linkage  J  and  bell-crank  /  shown.  The  suction  valve  plunger 
D  is  also  driven  by  a  fixed  eccentric  E  on  the  vertical  governor 
shaft,  being  180  degrees  behind  the  pump  plunger  eccentric. 
In  Fig.  136  the  pump  plunger  is  at  the  e  id  of  the  delivery  stroke 
while  the  suction  valve  plunger  is  at  the  extreme  inner  position. 
As  the  governor  shaft  revolves,  at  one-half  engine  speed,  the 
pump  plunger  moves  to  the  end  of  its  suction  stroke;  the  suction 
plunger  moves  outward,  lifting  the  suction  valve  off  its  seat,  this 
11 


162 


OIL  ENGINES 


allows  the  fuel  to  enter  the  pump  cavity.  As  the  pump  plunger 
reverses  and  moves  on  its  delivery  stroke,  the  suction  valve  re- 
mains open,  the  oil  flowing  back  into  the  suction  line.  At  a 
stated  point  in  the  pump  plunger  travel,  the  suction  plunger 
moves  out  of  contact  with  the  dog  F;  the  valve  now  closes  and 
the  oil  is  forced  out  through  the  discharge  valve.  If  the  load 
decreases,  the  rising  governor  sleeve  shifts  the  center  of  the  eccen- 
tric dog  bearing.  This  allows  the  valve  plunger  to  remain  in 


Governor  Collar:, 
in  Lowest" 
Position 


f— - 


FIG.   136.— Busch-Sulzer  type  B  Diesel  fuel  pump. 

contact  with  the  suction  valve  for  a  longer  interval,  which  per- 
mits more  of  the  fuel  charge  to  flow  back  into  the  suction  line. 

On  these  engines  there  is  a  pump  plunger  and  suction  valve 
plunger  for  each  engine  cylinder.  It  is  possible  to  use  only  one 
suction  valve  plunger,  but  this  individual  suction  valve  mechan- 
ism offers  opportunity  for  a  closer  adjustment  of  the  functioning 
of  each  pump.  On  some  of  the  four-cylinder  engines  the  four 
plungers  are  arranged  in  a  single  row,  while  on  others  there  are 
two  sets  of  two  plunger  cavities  each,  placed  end  to  end  with 
the  valve  block  in  the  center. 

This  fuel  pump  gives  the  closest  possible  speed  regulation 
while  the  reaction  on  the  governor  is  at  a  minimum.  The  re- 
sistance offered  to  the  movement  of  the  governor  sleeve  consists 
of  the  suction  valve  spring  compression. 

Filling  the  Fuel  Pump .— To  facilitate  charging  the  pump  and 
discharge  line  with  oil,  an  eccentric  shaft  L  is  provided.  This, 


FUEL  PUMPS  163 

shaft  is  rotated  by  means  of  a  hand  lever,  and,  by  so  doing,  the 
dog  F  is  raised  to  its  maximum  lift.  This  lifts  both  the  suction 
and  discharge  valves. 

Stopping  the  Engine. — A  less  angular  travel  of  the  eccentric 
shaft  L  lifts  only  the  suction  valve.  This  relieves  the  pumps  of 
the  oil  charge,  and  the  engine  stops  from  the  lack  of  fuel. 

Setting  Pump  Valves. — The  four  plunger  pumps  deliver  the 
fuel  to  the  four  cylinders  on  all  four  cycles,  i.e.,  suction,  compres- 
sion, expansion  and  exhaust  strokes.  In  timing  the  pump  and 
the  suction  valve  opening,  the  engine  is  slowly  turned  over,  and 
the  inner  and  outer  dead-centers  of  the  pump  plunger  eccentric 
are  marked  on  the  plunger.  The  engine  is  then  turned  over 
until  the  pump  plunger  is  %g  inch  from  its  discharge  dead-center. 
The  suction  valve  plunger,  or  regulating  plunger,  has  at  this 
point  moved  away  from  the  dog  or  bell-crank,  which  leaves  its 
contact  with  the  suction  valve  stem.  The  suction  valve  plunger 
should  be  adjusted  to  give  a  clearance  of  .002  inch  between  the 
dog  and  valve  stem  when  the  pump  plunger  is  in  the  position 
mentioned.  In  setting  the  valve,  the  governor  collar  must  be 
central.  In  a  two-plunger  pump  this  means  that  the  collar  must 
be  in  the  mid-point  of  its  travel,  while  with  a  four-plunger  pump 
the  collar  must  be  on  its  bottom  position;  to  obtain  the  latter 
the  governor  springs  must  be  removed. 

Pump  Valves. — 'The  engineer  need  give  but  slight  attention 
to  the  pump  other  than  to  the  valves.  Both  the  suction  and 
discharge  valves  wear  rapidly,  as  may  be  expected  of  any  type 
of  pump  valve  when  dirty  oil  is  handled.  In  regrinding,  emery 
flour  should  be  used,  placing  a  very  small  quantity  on  the  valve 
face.  In  some  engines  the  discharge  valve  spring  continually 
breaks.  It  is  hard  to  determine  the  cause;  at  times  a  lighter 
spring  relieves  the  trouble  while  on  other  pumps  a  heavier  spring 
is  required. 

Mclntosh  &  Seymour  Diesel  Full  Pump. — The  first  Diesels 
manufactured  by  the  Mclntosh  &  Seymour  Corporation  were 
equipped  with  fuel  pumps  somewhat  after  the  design  appearing 
in  Fig.  136.  The  engines  were  four-cylinder  units,  and  the  fuel 
pumps  had  two  pumping  plungers,  one  plunger  for  each  pair 
of  cylinders.  The  fuel  from  one  plunger  cavity  passed  through 
the  discharge  valve  and  pipe  line  into  a  block,  called  the  Dis- 
tributor. This  block  contains  two  passages  connected  to  the 
fuel  lines  leading  to  the  two  fuel  injection  valve.s.  The  cross- 


164  OIL  ENGINES 

sections  of  these  passages  are  controlled  by  needle  valves. 
The  fuel,  entering  the  distributor,  divides  into  two  streams;  the 
needle  valves  allow  the  operator  to  properly  proportion  the  two 
oil  streams. 

The  operating  difficulty  of  this  pumping  system  lies  in  the 
inability  of  the  engineer  to  regulate  the  distribution  of  the  fuel 
on  varying  loads.  A  setting  of  the  needles  that  is  correct  for 
full  load  will  not  give  the  proper  regulation  at  low  loads  since 
the  resistances  of  the  passages  vary,  due  to  a  smaller  quantity 
of  oil  entering  the  distributor.  Another  factor  that  prevents 
proper  proportioning  of  the  fuel  is  the  partial  clogging  of  one  line  ; 
this  throws  almost  all  the  oil  into  one  cylinder. 

With  this  form  of  pumping  mechanism  it  is  imperative  that  the 
oil  is  filtered  to  prevent  the  clogging  of  a  distributor.  Further- 
more, the  fuel  valves  must  be  kept  in  perfect  condition  since 
the  smallest  leak  in  a  fuel  injection  valve  lowers  the  resistance  of 
this  particular  fuel  line,  allowing  this  cylinder  to  receive  too  large 
a  proportion  of  the  fuel  from  the  pump. 

The  fuel  pump,  mentioned  above,  gave  way  to  a  design  which 
is  shown  in  Figs.  137  and  138.  Unlike  the  distributor  type 
pump  which  followed  Sulzer  Bros,  patents,  Fig.  137  is  of  exclu- 
sive American  design.  This  pumping  apparatus  consists  of 
two  pumps,  set  at  right  angles,  each  being  an  outside  packed 
double-plunger  pump.  The  eccentric  strap  E  driving  the  two 
plungers  is  mounted  on  an  eccentric  D,  and  the  governor  acts 
directly  on  the  pump  plungers,  in  this  way  regulating  the 
amount  of  fuel  pumped  by  varying  the  plunger  stroke.  The 
reaction  on  the  governor  of  direct  plunger  controlled  pumps  is 
considerable.  Mclntosh  &  Seymour  partially  avoid  this  by 
using  two  eccentrics;  the  eccentric  D,  controlled  by  the  governor, 
drives  the  pump  and  is  mounted  on  a  second  eccentric  B  that  is 
keyed  to  the  vertical  governor  shaft  C.  It  is  apparent  that  this 
offers  a  more  accurate  regulation  of  the  pump  stroke  and  a  greater 
reduction  in  the  reaction  on  the  governor  than  can  be  secured 
by  a  single  eccentric. 

The  pump  suction  valves  are  located  below  the  discharge 
valves,  being  removed  through  the  discharge  valve  opening.  The 
latter  valves  are  accessible  by  the  removal  of  the  valve  cap  or 
plug  G.  Below  the  suction  valves  of  the  two  pumps  is  placed  a 
shaft  H,  which  has  two  milled  cams,  as  shown  in  the  cross- 
section.  During  the  functioning  of  the  pump  the  suction  valve 


FUEL  PUMPS 


165 


FIG.  137. 


FIG.   138. — Governor  and  fuel  pump,  top  view. 


166  OIL  ENGINES 

stems  clear  the  shaft  by  means  of  the  depressions  in  the  shaft. 
Rotation  of  the  shaft  lifts  the  suction  valve,  thereby  filling  the 
pump  with  oil. 

Pump  Valves. — After  continued  regrindings  of  the  suction 
valve,  the  stem  touches  the  cam  at  its  lowest  -position.  This 
cocks  open  the  valve,  preventing  any  fuel  reaching  the  injection 
valve.  Grinding  the  end  of  the  stem  will  allow  it  to  clear  the 
cam.  This  same  trouble  frequently  occurs  in  regrinding  the  dis- 
charge valve,  causing  it  to  strike  the  suction  valve.  The  clear- 
ance between  the  two  should  be  approximately  ^{Q  inch. 

The  valve  springs  at  times  break.  This  is  probably  due  to 
fatigue;  replacement  by  a  spring  of  smaller  wire  in  most  cases 
seems  to  remedy  this  trouble.  The  discharge  valve  should  be 
allowed  a  lift  of  at  least  .025  inch.  The  valves  have  a  60-degree 
slope.  In  regrinding  more  care  is  necessary  than  with  a  45- 
degree  valve  seat. 

The  discharge  valve  cap  is  sealed  with  a  metallic  gasket. 
This  gasket  must  be  absolutely  clean  to  avoid  leaks.  Leaks 
around  the  valve  cap  are  quite  prevalent  with  many  makes  of 
pumps;  not  only  is  the  dripping  oil  unsightly  but  it  also  impairs 
the  engine  regulation. 

The  plunger  stuffing-box  glands  are  best  packed  with 
shredded  lead  or  vulcanbestos.  Watch  engineers  should  be  cau- 
tioned not  to  tighten  up  on  the  glands  with  too  great  a  pressure. 
This  binds  the  pump  plunger,  scoring  it  and  increasing  the  gover- 
nor reactions. 

Fuel  Pump  Timing. — The  fuel  pump  and  eccentrics  come  from 
the  factory  properly  timed,  and  no  change  is  necessary.  In 
case  it  appears  that  the  eccentric  has  slipped,  the  best  method  of 
checking  the  setting  is  to  place  the  engine  with  the  piston  of 
No.  1  cylinder  on  bottom  dead-center,  just  starting  the  compres- 
sion stroke;  in  this  position  the  pump  plunger  should  be  at  the 
end  of  its  delivery  stroke. 

Mclntosh  &  Seymour  Marine  Diesel  Fuel  Pump. —  The  Four- 
stroke-cycle  Marine  Diesel  of  this  make  is  equipped  with  a  fuel 
pump  along  somewhat  similar  lines.  In  this  pump,  Fig.  139,  six 
plungers,  placed  horizontally,  are  operated  by  eccentrics  mounted 
on  eccentrics.  This  second  set  of  eccentrics  is  keyed  to  the  pump 
shaft,  which  is  moved  lengthwise  by  means  of  the  manual  control 
lever.  These  eccentrics  are  made  with  their  axes  at  angles  with 
the  eccentric  shaft  center  line.  Shifting  the  shaft  lengthwise 


FUEL  PUMPS 


167 


increases  or  decreases  the  travel  of  the  pump  plungers;  the 
travel  of  the  plungers  can  be  completely  cut  out  by  reducing  the 
eccentric  throw  to  zero.  The  longitudinal  movement  of  this 


due  io  HandLi-Hvr,  ab'i  & 

Sec-Hon   C~C 


Fuel  Pump  Shaft 


Fuel  Pump Clu'kfi-  —     _j _j Top  of  Frame 


Section   A-A 


ift  0.025° 


Clearance,  Suction  Valve 


(Clearances,  Suction  Valve  Stem 
\foLi-rrer  Stem 


j/'j  Cyl.     I  2  34£6m 

;       [    ear  32  ,-- 


I'Futl 

Inlet-   - 


Sec-t-ion   B-B 
FIG.   139. — Mclntosh  &  Seymour  marine  four-stroke-cycle  Diesel. 

pump  shaft  is  accomplished  by  the  control  lever  through  the  air- 
starting  control  shaft,  as  has  been  discussed  in  Chapter  VIII. 
As  a  precaution  against  overspeeding,  a  governor  is  mounted 
on  the  pump  shaft  in  the  extension  case  of  the  pump  and  operates, 


168 


OIL  ENGINES 


through  a  linkage,  a  small  shaft  A,  which  raises  the  suction  valves. 
In  order  to  allow  a  single  cylinder  to  be  cut  out  at  will,  a  hand- 
lifter  is  provided  for  each  suction  valve.  Another  feature  of 
excellence  is  the  glass  cup  on  the  fuel  suction  line.  This  shows 
when  the  line  is  empty.  To  prime  the  engine  when  the  engine 
is  stopped,  a  handwheel  is  placed  on  the  pump  shaft,  a  few  turns 
of  which  fills  the  suction  line  and  pump  cavities. 


Position  ofHtdge 
-for  Maximum 
Stroke 


Starting  and 
Stopping  Handle 


Position  ofWsdge 
for  No  Stroke 


Suction 


FIG.  140. — McEwen  Bros.  Diesel  fuel  pump. 

Fuel  Pump  Timing. — For  each  cylinder,  the  pump  plunger 
must  be  at  the  end  of  its  delivery  stroke  when  the  piston  for  that 
particular  cylinder  is  at  bottom  dead-center,  just  beginning 
the  compression  stroke.  The  linkage  to  the  control  lever  must 
be  adjusted  to  give  the  pump  plungers  zero  travel  when  the  con- 
trol lever  is  at  both  the  start  and  stop  positions. 

McEwen  Diesel  Fuel  Pump. — The  McEwen  Diesel  has  an 
open-nozzle  fuel  valve;  consequently  the  pump  is  a  departure 


FUEL  PUMPS  169 

from  the  designs  already  discussed.  As  will  be  noted  in  Fig. 
140,  the  pump,  for  a  single-cylinder  engine,  consists  of  a  plunger 
housing,  to  which  is  bolted  the  valve  body,  and  the  pump  plunger 
with  actuating  mechanism.  In  action  the  cam,  through  the 
rocker  Z>,  moves  the  pump  plunger  E  to  the  left,  which  action 
forces  the  fuel  charge  out  through  the  discharge  line  to  the  fuel 
injection  valve.  As  the  cam  in  turning  releases  the  thrust  on 
the  rocker,  the  plunger  spring  forces  the  plunger  to  the  right; 
this  draws  in  a  charge  of  oil  through  the  suction  valve.  The 
pump  plunger  on  this  stroke  moves  to  the  right  until  it  strikes 
the  governor  wedge  C.  The  length  of  the  plunger  stroke  deter- 
mines the  amount  of  oil  entering  the  cylinder.  The  governor 
is  linked  to  the  wedge  C  and,  as  the  engine  speeds  up,  shoves 
the  wedge  farther  in,  decreasing  the  distance  from  the  wedge 
to  the  face  of  the  plunger  slot.  This  reduces  the  plunger  stroke. 

This  pump  is  one  of  the  simplest  in  use  and  has  the  advantage, 
as  have  all  wedge-governored  pumps,  of  offering  but  slight  re- 
sistance to  any  governor  movement.  The  reaction  on  the  wedge 
is  merely  that  due  to  the  plunger  spring  tension  when  the  wedge 
is  in  contact  with  the  plunger.  This  is  slight  and  occurs  only 
at  the  point  of  extreme  suction  travel  of  the  plunger.  As  a 
consequence,  the  governor  can  be  light  and  extremely  sensitive. 
This  is  of  distinct  advantage  in  alternating-current  work,  or  in 
any  other  work  necessitating  close  regulation. 

Pump  Valves. — Both  suction  and  discharge  valves  are  of  the 
poppet  wing  type  with  seats  having  a  60-degree  slope.  In 
regrinding  these  valves,  the  discharge  valve  must  not  be  lowered 
enough  to  prevent  a  proper  lift  of  the  suction  valve;  this  should 
be  at  least  .03  inch,  while  the  discharge  lift  works  best  with  a  lift 
of  around  ^4  inch. 

Pump  Plunger. — The  plunger  has  no  stuffing-box,  being  pro- 
vided with  sealing  grooves.  Since  the  pumping  head  is  very 
low,  but  little  leakage  will  occur  even  though  the  pump  sleeve 
is  considerably  worn. 

Pump  Timing. — The  pump  cam  is  keyed  to  the  engine  lay- 
shaft  and  requires  no  alteration  in  timing.  However,  the  pump 
plunger  should  be  at  the  end  of  its  discharge  stroke  when  the 
engine  piston  is  on  out  dead-center,  just  starting  the  compression 
stroke. 

In  setting  the  governor  wedge  for  no-load  conditions,  after  the 
weights  are  thrown  out  to  their  greatest  travel,  the  wedge  should 


170 


OIL  ENGINES 


>be  moved  in  until  the  slot  is  in  contact  with  the  thickest  part  of 
the  wedge.  Then  after  throwing  the  pump  plunger  to  the  end 
of  its  discharge  by  turning  the  engine  over,  there  should  be  not 
more  than  .01-inch  play  between  the  wedge  and  the  inner  edge 
of  the  slot.  This  is  the  position  of  the  wedge  when  no  fuel  is 
pumped.  For  full-load  condition,  at  which  event  the  weight 
arms  are  at  their  maximum  position,  the  wedge  should  have 
moved  in  the  slot  so  that  the  slot  edge  just  strikes  the  wedge 
at  the  point  where  the  wedge  slope  begins.  This  point  should 
be  2J£  inches  from  this  first  or  no-load  position. 


FIG.  141. — Snow  Diesel  fuel  pump. 

Snow  Diesel  Fuel  Pump. — The  Snow  Diesel  engine  has  a 
fuel  pump  designed  with  wedge  control.  This  pump,  which 
appears  in  Fig.  141,  has  the  plunger  in  two  sections.  The  driving 
end  of  this  plunger  is  hollow  and  carries  the  slot  for  the  wedge. 
It  is  also  provided  with  a  pin  which  bears  against  the  cam  lever 
roller  at  all  times,  being  held  by  a  compressed  spring.  With  this 
design,  on  short  plunger  strokes,  as  on  low  load,  the  roller  does 
not  strike  the  plunger  end  when  traveling  at  maximum  speed. 
Instead  the  plunger  pin  moves  in,  being  resisted  by  the  spring, 
until  the  spring  compression  overcomes  the  pump  plunger  resist- 


FUEL  PUMPS  171 

ance.  At  this  point  the  pump  plunger  starts  on  the  delivery 
stroke.  The  result  is  a  quiet  pump  with  a  minimum  of  wear  and 
shocks  on  the  mechanism.  The  plunger  wedge  is  fastened  to  the 
reach-rod  A,  which  is  under  control  of  the  governor. 

Pump  Valves. — The  pump  valves  are  of  the  ball  type.  In 
case  leaks  develop,  a  hardwood  stick  can  be  placed  on  the  ball 
and  struck  a  light  blow  with  a  hammer.  This  will  give  the  ball 
a  new  seat  on  the  housing.  In  event  the  ball  is  scored  or  rough, 
the  only  remedy  is  replacement  with  a  new  ball;  even  here  the 
ball  must  be  given  a  new  seat  in  the  housing.  The  ball  valve, 
if  it  has  any  great  amount  of  lift,  is  sluggish  in  closing.  A  lift 
for  a  pump  ball  valve  ought  never  to  exceed  ^{Q  inch.  If  more 
than  this,  a  light  coil  spring  should  be  inserted  above  the  ball 
to  quicken  its  action. 

Timing  the  Pump. — In  adjusting  the  pump  plunger  for  no- 
load  and  full-load  strokes,  the  reach-rod  A  should  be  adjusted 
to  allow  the  plunger  to  touch  the  wedge  at  the  beginning  of  the 
wedge  slope,  when  the  governor  is  at  its  lowest  position,  which 
is  the  full-load  condition.  For  no  load,  when  the  governor  is 
blocked  open,  the  wedge  should  have  moved  to  a  position  where 
the  plunger  has  a  slight  clearance  between  the  slot  edge  and 
the  wedge,  on  the  inner  position  of  the  pump  plunger. 

Allis -Chalmers  Diesel  Fuel  Pump. — The  fuel  pump  used  on 
the  Allis-Chalmers  engine  is  shown  in  Fig.  142.  The  pump 
plunger  is  actuated,  through  a  rock-shaft  D  and  the  con- 
nection rod  C,  by  the  fuel  cam  below  the  pump.  The  plunger 
rock-shaft  D  is  fulcrumed  at  E  on  the  lever  F,  which  is  under 
control  of  the  governor  through  the  reach-rod  G.  As  the  engine 
speeds  up,  the  reach-rod  moves  downward;  this  raises  the  ful- 
crum pivot  E.  This  motion  of  the  fulcrum  raises  the  pump 
plunger  A  until  its  end  is  above  the  by-pass  slot  H  at  the  end 
of  the  suction  stroke  since  the  plunger  spring  holds  the  rod  C 
in  contact  with  the  cam  B.  As  the  cam  rotates,  the  plunger 
receives  a  constant  stroke,  but,  since  part  of  the  stroke  occurs 
before  the  by-pass  slot  is  covered  by  the  plunger,  the  first  portion 
of  the  oil  displaced  by  the  plunger  flows  through  the  slots  H. 
As  soon  as  the  plunger  passes  the  slots,  the  oil  below  the  plunger 
is  forced  through  the  discharge  valve  to  the  atomizer.  Since 
an  open-nozzle  fuel  valve  is  employed  in  connection  with  the 
pump,  the  latter  has  but  the  pipe  resistance  to  overcome.  The 


172 


OIL  ENGINES 


governor,  then,  is  called  upon  to  oppose  only  a  slight  reaction 
and  consequently  can  be  sensitive  without  danger  of  hunting. 
The  cam  connection  rod  C  is  provided  with  a  special  head 
having  adjusting  set-screws.  Proper  manipulation  of  these 
set-screws  will  alter  the  effective  stroke  of  the  pump  plunger. 


DISCHARGE- 
VALVE 


FIG.  142. — Allis-Chalmers  Diesel  fuel  pump. 

In  stopping  the  engine  the  hand  lever  is  raised,  allowing  the 
release  band  J  to  grip  the  lock  I  on  the  rod  C.  This  prevents 
the  rod  from  dropping  into  contact  with  the  cam.  In  starting, 
the  handle  is  used  to  prime  the  pump. 

The  pump  is  fitted  with  a  plunger  and  rocker  mechanism  for 
each  cylinder  of  engine,  with  individual  cams  on  the  lay  shaft. 


FUEL  PUMPS 


173 


De  La  Vergne  FD  Diesel  Fuel  Pump. — Figure  143  is  an  external 
view  of  the  fuel  pump  used  on  the  FD  engine.  The  governor- 
acts  upon  a  by-pass  valve  a  through  a  system  of  levers.  The 
fuel  charges  are  controlled  by  the  movement  of  this  by-pass 
valve. 


FIG.  143. — De  La  Vergne  type  FD  Diesel  fuel  pump. 


Nelseco  Marine  Diesel  Fuel  Pump. — The  fuel  pump  fitted  to 
the  Nelseco  Marine  Diesel  appears  in  Fig.  144.  The  engine 
speed  can  be  altered  by  the  control  lever  shown,  through  a 
linkage  which  alters  the  position  of  the  governor  lever  fulcrum. 
The  governor  then  maintains  this  desired  speed  by  changing  the 
period  of  suction  valve  opening.  The  fuel  pump  consists  of 
the  working  plunger  driven  by  an  eccentric,  and  the  suction  and 
discharge  valves.  The  suction  valve  is  held  open  through 


174 


OIL  ENGINES 


part  of  the  delivery  stroke  of  the  pump,  the  length  of  this  period 
being  under  governor  control. 


Timing  Fuel  Pump.— To  adjust  the  pump  proceed  as  follows :  Set 
the  fuel  control  lever  at  division  No.  1  and  lock.     Bar  the  engine 


FUEL  PUMPS 


175 


over  until  some  two  plungers  are  at  the  inner  end  of  their  stroke. 
Then  adjust  the  adjusting  screw  on  the  corresponding  suction 
valves  until  a  piece  of  paper  placed  between  the  adjusting 
screw  point  and  the  fuel  suction  valve  end  is  just  barely  held. 
Adjust  all  the  other  suction  valves  in  the  same  way,  still  keeping 
the  fuel  control  handle  locked  in  the  same  place. 

National  Transit  Diesel  Fuel  Pump. — The  fuel  pump  on  the 
first  National  Transit  engines  has  a  differential  plunger,  the 
upper  end  being  hollow  and  provided  with  a  cut-off  valve,  Fig. 


FIG.   145. — National  Transit  Diesel  fuel  pump,  old  model. 

145.  This  differential  plunger  is  driven  by  an  eccentric  keyed 
to  the  camshaft.  The  cut-off  valve  is  under  control  of  the 
governor  through  a  link  and  bell-crank.  The  pump  functions 
as  follows:  On  full  load  the  governor  sleeve  is  as  shown  in  the 
figure;  this  position  is  such  that  the  cut-off  valve  leaves  its 
seat  on  the  plunger  as  soon  as  the  latter  starts  on  the  downward 
or  suction  stroke.  The  oil  is  then  drawn  through  the  suction 
valve  and  fills  the  passage  in  the  plunger  and  the  chamber  A 
above  the  differential  plunger.  On  the  upward  or  discharge 
stroke,  the  cut-off  valve  being  open,  the  large  end  of  the  plunger 


176  OIL  ENGINES 

displaces  the  oil  in  this  chamber  and  forces  it  down  through  the 
plunger  and  out  the  discharge  valve.  On  low  loads  the  governor 
bell-crank  moves  downward;  this  allows  the  valve  to  remain 
seated  on  the  plunger  during  part  of  the  downward  stroke.  As 
soon  as  the  plunger  moves  below  this  point,  the  valve  rests  on 
the  bell-crank  fingers  and  leaves  its  seat.  The  chamber  fills 
with  oil,  and  on  the  upward  stroke  the  fuel  is  forced  out  the 
discharge  valve  until  the  plunger  comes  in  contact  with  the  cut- 
off valve.  The  cut-off  valve  then  seats,  and  all  the  oil  displaced 
by  the  further  movement  of  the  plunger  passes  out  through  the 
overflow  valve  B  at  the  top  of  the  pump  body. 

Pump  Valves. — To  insure  close  regulation,  the  cut-off  valve 
seat  must  be  in  good  condition.  Even  though  it  is  rather  un- 
handy to  reach,  at  least  monthly  the  valve  should  be  removed 
and,  if  the  seat  is  not  smooth,  it  should  be  reground.  To 
remove  the  valve,  the  overflow-pipe  joint  can  be  broken  and  the 
check- valve  cage  lifted. 

Timing  Fuel  Pump. — The  plunger  eccentric  is  keyed  to  the 
camshaft,  and  no  change  of  the  timing  is  necessary. 

In  timing  the  cut-off  valve,  the  valve  should  just  start  to  leave 
the  seat  as  the  pump  plunger  commences  its  downward  stroke 
when  the  governor  is  at  rest  and  the  collar  in  its  lowest  position. 
This  is  the  full-load  position.  The  governor  springs  should  then 
be  removed  and  the  weights  moved  to  their  maximum  outward 
positions,  which  raises  the  collar  to  its  highest  point.  The  cut- 
off valve  should  now  be  seated  on  the  plunger  during  the  entire 
stroke  of  the  plunger,  with  the  exception  of  about  Jiooo 
inch.  This  is  the  no-load  position  of  the  valve.  An  adjusting 
lever  and  lock  C  are  placed  on  the  bell-crank  outside  of  the  casing. 
This  allows  the  timing  of  the  valve  to  be  altered  to  conform  to 
the  desired  setting.  To  stop  the  engine  this  lever  is  moved  to 
lower  the  cut-off  valve. 

National  Transit  1918  Diesel. — The  later  National  Transit 
Diesels  are  supplied  with  a  fuel  pump  that,  in  form,  resembles 
the  pump  discussed  above  but  which  functions  on  an  entirely 
different  principle.  This  pump  appears  in  Fig.  146.  In  this 
design  the  pump  plunger  is  actuated  by  a  rocker  and  cam  in  place 
of  the  former's  eccentric  and  strap.  The  plunger  P  is  hollow 
and  carries  at  its  top  the  cut-off  valve  V.  This  valve  has  a  tri- 
angular shank  which  extends  down  into  the  hollow  plunger,  and 
the  valve  is  controlled  by  the  fingered  or  forked  lever  E.  This 


FUEL  PUMPS 


177 


FIG.  146. — Fuel  pump  arid  governor,  type  D-3.     National  Transit  Diesel. 


178  OIL  ENGINES 

lever  is  moved  by  the  governor  and  limits  the  downward  travel 
of  the  valve  V.  As  the  plunger  is  forced  downward  on  its  suction 
stroke  by  the  spring  S,  the  oil  enters  the  pump  body  at  the  open- 
ing A  and,  passing  through  the  ports  B,  enters  the  hollow  plunger. 
Since  the  lever  E  has  engaged  the  valve  V  at  some  point  on  the 
downward  stroke  of  the  plunger  P,  this  valve  is  open  and  the  oil 
fills  the  cavity  J.  On  the  upward  stroke  of  the  plunger  the  oil 
displaced  flows  back  through  the  open  cut-off  valve  V,  through 
the  ports  B  and  suction  opening  A,  to  the  source  of  supply.  As 
the  plunger  continues  its  travel,  it  comes  in  contact  with  the  valve 
Vj  which  thereupon  seats  at  D.  The  continued  travel  of  the 
plunger  entails  a  further  displacement  of  oil,  which  lifts  the  dis- 
charge valve  H  and  is  forced  to  the  fuel  injection  nozzle.  It  will 
be  observed  that,  while  with  the  pump  in  Fig.  145  on  no  load  the 
cut-off  valve  was  closed  during  the  entire  plunger  stroke,  with 
this  pump  the  cut-off  or  suction  valve  V  is  opened  during  the 
entire  plunger  stroke  when  the  governor  is  in  the  no-load  posi- 
tion. This  change  in  design  eliminates  the  suction  valve  and 
the  overflow  valve  while  improving  the  fuel-measuring  accuracy 
of  the  pump. 

Standard  Fuel  Oil  Diesel  Engine  Fuel  Pump. — The  pump  of 
this  two-cycle  Diesel  engine  is  illustrated  in  Fig.  147.  The  fuel 
pump  is  a  plain  barrel  B,  having  a  plunger  directly  under  the 
influence  of  a  Rites  Inertia  governor.  The  barrel  and  plunger 
A  is  the  air  injection  control.  Both  the  suction  and  discharge 
openings  have  two  sets  of  wing  poppet  valves.  The  pump 
plunger  is  pivoted  to  a  bell-crank  which,  in  turn,  is  driven  by  the 
eccentric  rod.  The  eccentric-rod  side  of  the  crank  has  a  worm- 
screw  adjustment  whereby  the  stroke  of  the  pump,  for  any  given 
position  of  the  governor  weight  arm,  may  be  altered.  Lowering 
the  rod  end  gives  a  greater  stroke  to  the  pump  plunger,  and 
raising  it,  a  lessened  stroke.  In  timing  the  engine  a  good  prac- 
tical plan  to  set  the  pump  stroke  for  no-load  conditions  is  to  first 
lower  the  eccentric  until  the  engine  speeds  up  above  normal. 
Then  the  eccentric  rod  should  be  raised  by  the  screw  until,  at 
a  slight  overspeed,  the  plunger  movement  is  zero.  This  posi- 
tion of  the  eccentric  end  should  give  sufficient  stroke  to  the 
plunger  at  the  full-load  position  of  the  governor. 

In  stopping  the  engine  the  lock  screw  C  is  loosened,  cutting 
out  the  pump.  Since  the  engine  is  two-cycle,  the  pump  works 
against  a  much  greater  pressure  than  exists  with  a  four-stroke- 


FUEL  PUMPS 


179 


cycle  engine,  even  though  an  open  nozzle  is  employed  on  both 
engines.  For  this  reason  the  wear  on  the  pump  valves  is  greater, 
and  regrinding  is  more  frequent.  The  engineer  must  give  special 
attention  to  the  plunger  stuffing-box,  as  a  small  leakage  effects 
the  engine's  regulation. 


FIG.   147. — Standard  fuel  oil  Diesel  fuefpump. 

General. — After  the  valves  of  any  design  of  fuel  pump  have 
been  replaced,  after  grinding,  etc.,  the  discharge  line  should  be 
disconnected  from  the  injection  valve,  if  no  by-pass  valve  is 
attached.  The  pump  should  then  be  primed.  This  will  effect 
the  escape  of  any  air  that  might  be  trapped  in  the  pump  cylinder. 


180  OIL  ENGINES 

In  case  the  engine,  on  starting,  fails  to  fire  on  any  particular 
cylinder,  the  pump  is  probably  air-bound,  and  the  lines  must  be 
freed  before  oil  will  enter  the  fuel  valve.  At  times  the  fuel-line 
check  valve  leaks,  allowing  air  to  flow  down  the  pipe  to  the  fuel 
pump.  This  will  prevent  the  pump  from  delivering  any  oil. 

Valve  Grinding. — In  grinding  any  poppet-type  valve  powdered 
glass,  or  emery  flour,  and  vaseline  make  the  best  compound. 
The  operator  must  exercise  judgment  in  the  amount  of  pressure 
exerted  on  the  valve  as  it  is  rotated.  If  the  pressure  is  excessive, 
the  compound  will  groove  the  valve  faces. 

When  a  discharge  valve  or  suction  valve  is  under  suspicion, 
the  best  method  of  ascertaining  if  it  actually  leaks  is  to  disconnect 
the  discharge  line  and  place  on  the  coupling  a  high-pressure  gage. 
The  engine  can  be  turned  over  until  the  pump  discharge  pressure 
registers  the  usual  value,  900  Ibs.  with  closed  nozzle  and  about 
200  Ibs.  with  open  nozzle.  The  engine  should  then  be  stopped 
and  the  discharge  pressure  noted.  If  it  falls,  it  can  be  taken  as 
an  indication  of  a  leaky  valve. 


CHAPTER  XI 
GOVERNORS 

TYPES.     ADJUSTMENTS 

Governors. — When  an  engine  is  carrying  a  constant  load,  the 
fuel  pump  delivers  to  the  engine  cylinders  just  enough  fuel  to 
enable  the  engine  to  overcome  the  resistance  at  the  flywheel  and 
the  frictional  resistance  of  the  engine  itself.  This  condition 
never  exists  in  a  power  plant.  The  load  may  decrease,  with  the 
result  that  the  fuel  injected  into  the  engine  cylinder  is  greater 
than  is  necessary  to  overcome  the  lessened  load.  The  engine 
would  then  speed  up  and  wreck  itself.  If  the  load  increased, 
the  fuel  charge  would  be  insufficient  and  the  engine  would 
slow  down  and  finally  cease  turning.  Some  form  of  fuel  control 
is  then  imperative.  On  the  marine  Diesel,  when  the  engineer 
is  in  constant  attention  upon  the  unit,  a  manual  control  is  pro- 
vided. This  consists  of  some  form  of  leverage  that  alters  the 
pump  stroke  or  the  period  of  pump  suction  valve  opening.  Even 
with  the  marine  engine  an  automatic  overspeed  device  is  usual 
to  prevent  disaster  in  event  of  non-attention  on  the  part  of  the 
operator.  The  stationary  engine  receives  no  such  attention 
since  the  engineer  has  many  other  duties  to  perform.  Further- 
more, a  speed  variation  permissible  on  a  marine  engine  cannot  be 
allowed  in  an  engine  pulling  either  a  central  station  or  an  indus- 
trial load.  To  obtain  the  speed  regulation  that  such  loads 
impose  the  device  called  a  governor  is  used. 

The  close  regulation  of  an  engine's  speed  requires  that  the 
governor  must  be  sensitive  to  speed  changes.  To  attain  this 
object  the  governor  should  possess  a  minimum  internal  frictional 
resistance,  or  otherwise  too  great  a  speed  change  will  be  reached 
before  the  governor  overcomes  its  resistance  and  moves  the  con- 
trol lever.  It  is  clear  that,  without  any  internal  resistance,  the 
governor  would  respond  to  an  infinitesimal  change  in  engine 
speed  with  the  result  that  the  speed  would  be  constant,  within 
the  power  of  observation.  This  internal  resistance  produces  a 
sluggishness  in  the  governor  action  which  can  be  given  a  numer- 
ical value  by  defining  it  as  the  proportion  which  the  change  in 

181 


182  OIL  ENGINES 

speed  necessary  to  produce  the  required  governor  movement 
bears  to  the  total  speed.  That  is,  if  NI  is  the  speed  at  which  the 
engine  has  been  turning  and  7V2  is  the  speed  the  engine  attains, 
at  a  change  in  load,  before  the  governor  acts  upon  the  fuel  pump, 
then 


can  be  termed  the  sluggishness  of  the  governor.  For  many 
kinds  of  work  this  value  must  be  as  small  as  possible;  a  value 
of  Koo  is  satisfactory  in  service.  To  secure  this  value  the  gover- 
nor must  be  free  from  excessive  friction;  in  other  words,  it  must 
be  sensitive.  This,  in  many  forms  of  governors,  produces  a 
"hunting"  effect  wherein  the  governor  is  constantly  changing 
the  position  of  the  weights  in  order  to  meet  the  engine  speed 
changes.  Since  the  governor  movement  always  follows  the 
change  in  speed,  if  the  governor  is  sensitive  it  may  over-travel 
in  meeting  a  speed  increase;  this  over-travel  will  cause  the 
engine's  revolutions  to  decrease  below  normal;  the  latter  then 
produces  a  governor  movement  which  results  in  another  increase 
in  speed  above  normal.  It  is  necessary  that  the  governor  sleeve 
has  the  same  lifting  force  in  every  position  for  a  given  change 
of  speed.  Furthermore,  the  engine  flywheel  must  be  of  ample 
size  to  absorb  the  speed  fluctuations  occurring  during  one  cycle 
of  the  engine. 

To  avoid  the  "  hunting"  effect  mentioned  above,  some  gov- 
ernors are  fitted  with  one  of  many  designs  of  dashpots.  Some 
of  these  dashpots  consist  of  oil  cylinders  containing  a  piston 
connected  'to  the  governor-sleeve  lever,  having  a  passage  be- 
tween the  two  ends  of  the  cylinder  through  which  the  oil  can 
pass.  This  provides  a  resistance  to  prevent  a  governor  move- 
ment due  to  any  sudden  speed  change.  The  oil  flows  through 
the  opening,  thus  allowing  the  governor  to  cope  with  any  per- 
manent change  in  engine  speed.  This,  of  course,  makes  the 
engine  slow  in  action. 

While  the  desirable  governor  must  not  be  sluggish,  it  does  not 
follow  that  a  sensitive  governor  holds  the  engine  speed  within 
narrow  limits  on  a  change  from  no  load  to  full  load  unless  a 
correct  design  of  pump  is  chosen.  Much  depends  upon  the 
effort  which  must  be  exerted  on  the  fuel  pump  mechanism  to 
bring  it  from  its  minimum  pumping  position  to  its  maximum 


GOVERNORS  183 

position.  Since  a  large  change  in  engine  speed  gives  the  gov- 
ernor a  maximum  force  to  exert  on  the  pump,  it  follows  that 
the  greatest  permissible  fluctuation  in  engine  speed  should  be 
adopted  to  give  the  governor  a  high  work  capacity.  A  6  per  cent, 
fluctuation  or  3  per  cent,  variation  above  or  below  normal  speed 
is  quite  satisfactory  for  oil-engine  governing.  It  does  not  follow 
that  this  variation  occurs  on  any  save  extreme  load  changes. 
In  the  load  changes  that  ordinarily  take  place,  the  fluctuations 
would  not  exceed  1  per  cent,  since  the  governor-sleeve  travel  is 
small  on  small  load  changes. 

American  Diesel  Governor. — The. governor  of  the  American 
Diesel  and  the  Busch-Sulzer  Type  A  engines  is  of  the  fly-ball 
type.  The  two  weight  arms  W,  which  are  held  by  a  spring  at 
RR,  Fig.  135,  act  upon  a  sleeve  ~S,  which  in  turn  raises  or  lowers 
a  lever  L.  This  lever  is  connected  by  the  link  K  to  the  fuel 
pump  suction  valve  rocker  shaft  C  and  alters  the  period  of 
valve  opening,  as  described  in  the  preceding  chapter.  To 
absorb  small  speed  variations  an  oil  dashpot,  not  shown,  is 
linked  to  the  governor-sleeve  lever  at  /;  a  speed  regulator  is  also 
included,  this  being  in  the  form  of  a  weighted  arm  as  appears  in 
the  illustration  at  T.  As  a  protection  in  event  the  governor 
breaks,  a  safety  weight  arm  is  fitted  to  the  fulcrum  shaft.  This 
weight  will  pull  the  shaft  into  the  inoperative  position  if  the 
governor  links  break.  This  governor  is  not  of  a  type  that  allows 
any  great  permanent  change  in  the  engine  speed;  20  per  cent,  is 
as  much  as  can  be-  obtained  while  maintaining  the  governor's 
stability. 

Adjustments. — The  governor  shows  a  decided  tendency  to 
wear  at  the  links  and  pins.  About  every  two  years  it  is  necessary 
to  reream  the  link-pin  bearings  and  turn  up  new  pins.  These 
pins  are  best  made  of  brass  to  allow  the  wear  to  occur  on  the  pins 
rather  than  on  the  links.  It  is  much  easier  to  turn  up  new  pins 
than  it  is  to  re-ream  the  links.  For  the  latter  purpose  an  expan- 
sion rereamer  is  more  serviceable  than  is  the  ordinary  kind.  The 
blades  can  be  extended,  giving  a  greater  capacity  for  reaming. 

Jahns  System. — The  Jahns  governor  has  been  adopted  by  the 
builders  of  the  Busch-Sulzer  Type  B  Eiesel,  the  Snow  Diesel,  and 
the  National  Transit  Diesel. 

The  construction  of  the  Jahns  governor  may  be  readily  seen 
from  Figs.  148  and  149.  The  two  weights  AA  are  guided  in  a 
radial  straight  line  perpendicular  to  the  spindle  by  three  rolls 


184 


OIL  ENGINES 


C  on  the  lower  surface  sustaining  the  weights,  and  two  rolls,  not 
shown,  on  the  sides  resisting  the  force  of  inertia  which  would 
tend  to  keep  the  weights  revolving  at  the  same  rate  while  the 
engine — and,  therefore,  the  governor  casing — increases  or  decreases 
its  speed  by  an  infinitesimal  amount.  The  centrifugal  force  of 
each  weight  acts  directly  upon  its  spring  so  that  all  lever  joints 
are  entirely  free  from  any  centrifugal  or  spring  force. 


FIG.   148. — System  Jahns  governor. 

The  transmission  of  the  motion  of  the  weights  to  the  sliding 
sleeve  on  the  spindle  is  effected  by  the  bell-cranks  D  fulcrumed 
on  the  lower  casing,  the  upper  arms  engaging,  by  means  of  rolls, 
the  vertical  straight  slots  in  the  weights,  while  the  lower  arms 
engage  sloping  slots  in  the  spindle  sleeve  F.  The  angle  of  this 
slope  is  fixed  in  such  a  manner  that  the  centrifugal  force  of  the 
weights,  as  transmitted  to  the  sleeve,  is  a  practically  constant 
force,  being  the  same  for  each  position  of  the  sleeve  throughout 
its  stroke.  The  collar  G  to  which  is  connected  the  pump-control 
lever  receives  its  motion  from  the  spindle  collar. 

The  Jahns  governor  casing  is  entirely  enclosed,  and  all  of  the 
lower  pins  and  slides  are  in  a  bath  of  oil.  The  oiling  of  the  upper 
pins  and  slides  is  effected  thr  ough  the  oil  cup  on  the  top  of  the 


GOVERNORS 


185 


governor.  This  oiling  can  be  effected  while  the  governor  is  in 
motion.  When  the  oil  has  attained  a  certain  height  any  addi- 
tional amount  will  cause  overflow.  This  surplus  is  conducted 
to  the  rubbing  surfaces  of  the  sliding  spool  located  below  and 
outside  of  the  casing.  In  this  manner  every  point  of  possible 
friction  is  automatically  oiled. 

The  Jahns  governor  possesses  great  sensitiveness  owing  to  its 
extremely  small  internal  friction  and  the  fact  that  none  of  the 
working  parts  may  become  rusted  or  clogged  with  dust. 

Owing  to  its  low  internal  resistance,  the  Jahns  governor  has  great 
capacity,  the  percentage  of  available  energy  for  regulation  as 
compared  with  the  total  energy  developed  by  the  weights  being 
99.8  per  cent. 


FIG.   149. — Busch-Sulzer  type  B  Diesel  Jahns"governor. 

The  Jahns7  governor,  as  supplied  on  the  oil  engine,  always  has 
a  speed  regulator  attached.  This  regulator  is  usually  made  to 
give  a  variation  of  plus  and  minus  5  per  cent,  of  the  standard 
speed.  The  arrangement  of  the  governor  and  regulator  varies 
slightly  in  each  engine. 

Busch-Sulzer  Diesel  Governor. — The  Jahns  governor  fitted 
to  the  Busch-Sulzer  engine  appears  in  Fig.  149.  The  governor 


186  OIL  ENGINES 

sleeve  is  placed  above  the  governor  case  rather  than  below  as  is 
the  standard  practice.  This  brings  the  sleeve  within  range  of  the 
fuel  pump.  The  governor  acts  on  the  suction  valve,  as  shown 
in  Fig.  136. 

An  overspeed  governor  is  also  placed  on  the  Busch-Sulzer 
engine.  This  is  of  the  ordinary  centrifugal  weight  design.  If 
the  engine  overspeeds,  the  weight  strikes  a  lever  which  releases 
a  catch  on  a  relief  valve.  This  allows  the  oil  to  by-pass  back  to 
the  supply. 

Snow  Diesel  Governor. — The  Snow  engine  is  equipped  with 
the  Jahns  governor  with  the  regulator  as  appears  in  Fig.  91. 
On  some  of  the  engines,  where  a  great  speed  range  is  required, 
the  class  D  Jahns  governor  is  used.  This  governor  is  identical 
with  the  class  C  governor  with  the  exception  of  the  regulator, 
Fig.  11.  The  regulator  spring  is  located  in  the  governor  stand 
and  surrounds  the  spindle,  rotating  with  the  latter.  The  lower 
end  of  the  spring  rests  on  a  cross-key  passing  through  a  rod  inside 
the  hollow  governor  spindle.  This  rod  is  fastened  to  the  roll 
sleeve  inside  the  governor.  The  upper  end  is  in  contact  with  a 
ball-bearing  collar  having  two  ears  passing  through  slots  in  the 
governor  pedestal.  The  pedestal  is  threaded  and  has  a  hand- 
wheel  holding  the  spring  collar  ears.  Turning  the  wheel  gives 
the  necessary  spring  compression  for  any  speed  within  50  per 
cent,  of  normal.  With  this  governor  the  ball-races  should  be 
cleaned  occasionally  to  remove  dirt  and  gum. 

National  Transit  DieseF  Governor. — The  National  Transit 
Co.  provide  their  engine  with  the  Jahns  type  C  governor,  Fig. 
145,  although  the  class  D  is  used  to  meet  wide  speed  range  re- 
quirements. Figure  146  shows  the  class  D  governor  connected 
to  the  fuel  pump. 

McEwen  Diesel  Governor. — The  governor  of  the  McEwen 
Diesel  is  of  the  centrifugal  weight  type.  The  governor,  Fig.  150, 
consists  of  two  weights  A  that  are  held  together  by  a  spring- 
loaded  rod  B  which  passes  through  the  engine  lay  shaft.  Two 
sets  of  bell-cranks  connect  the  governor  weights  with  the  gov- 
ernor sleeve  D  and  are  fulcrumed  on  the  spider  H.  The  sleeve 
D  extends  along  the  shaft  between  the  two  weights  and  has  a 
yoke  and  lever  connected  to  the  fuel  pump  wedge.  Any  change 
of  engine  speed  causes  the  weights  to  take  new  positions;  this 
shifts  the  sleeve  along  the  shaft,  causing  the  fuel  pump  wedge 
to  shorten  or  lengthen  the  pump  plunger  stroke. 


GOVERNORS 


187 


FIG.   150. — McEwen  Diesel  governor. 

.-TO  Fuel  Pump 


SLEEVE 


WC16HT- 


^- 'WEIGHT 
PRINQ 


'SPRING  BOLT 


OVERNOR  DRIVING 
SHAFT 


FIG.   151.— Allis- Chalmers  Diesel  governor. 


188  OIL  ENGINES 

Adjustments. — With  this  type  of  governor  about  the  only 
attention  required  is  the  cleaning  of  all  the  parts.  If  the  pins 
and  rollers  are  allowed  to  become  foul  with  grit  and  grime,  the 
wear  will  result  in  considerable  lost  motion.  This  causes  the 
engine  to  be  erratic  in  speed  regulation. 

Allis -Chalmers  Diesel  Governor. — The  governor  of  the  Allis- 
Chalmers  Diesel  appears  in  Fig.  151.  The  governor  spindle 
carries  a  yoke-shaped  frame  which  revolves  with  the  spindle. 
To  the  frame  is  hung  two  weights  which  are  held  together  by  two 
spring  bolts  and  one  spring.  The  spring  is  in  tension,  rather 
than  compression  as  is  the  usual  governor  practice.  At  an  in- 
crease in  the  engine  speed,  which  is  communicated  to  the  weights 
through  the  layshaft  and  the  spindle,  the  weights  move  outward. 
The  motion  is  translated  to  the  regulator  connection  by  the  yoke 
levers.  The  regulator  connection  raises  and  shifts  the  pump 
lever  as  described  in  Chapter  XI. 

This  governor  has  the  advantage  that  lies  in  the  employment 
of  but  one  weight  spring.  It  is  practically  impossible  to  secure 
two  springs  possessing  the  same  characteristics.  Where  two 
springs  are  used  the  outward  travel  of  the  two  weights  will  not 
be  equal,  throwing  a  side  thrust  on  the  spindle. 

Adjustments. — Speed  regulation  is  secured  by  the  spring  bolt, 
while  shifting  the  weight  on  the  outside  lever  will  give  a  small 
speed  change. 

A  disk  step  bearing  is  fitted  to  the  base  of  the  governor  spindle. 
This  consists  of  two  steel  disks  and  one  bronze  disk.  The 
bronze  disk  wears  from  the  weight  of  the  governor  and  the 
thrust  of  the  helical  gear.  As  soon  as  the  gear  emits  a  grinding 
sound,  the  operator  should  examine  the  step  bearing  since,  when 
it  wears,  it  causes  the  gears  to  mesh  improperly. 

Standard  Fuel  Oil  Diesel  Governor.  —  The  Rites  Inertia 
governor  is  used  on  this  engine.  The  governor  eccentric  gives 
a  variable  throw  to  the  fuel  pump  plunger.  -  The  governor 
is  fitted  with  a  dashpot  to  eliminate  the  super-sensitiveness  that 
is  inherent  in  this  form  of  shaft  governor.  The  governor  has 
the  advantage  of  being  extremely  simple  and  devoid  of  wear  with 
the  exception  of  the  governor  pin  bushing.  This  must  be  well 
lubricated.  A  change  of  speed  can  be  secured  by  altering  the 
spring  tension.  The  regulation  can  be  varied  by  shifting  the  lo- 
cation of  the  spring  bolt  in  the  governor  slot — moving  the  bolt 
in  toward  the  center  makes  the  governor  more  sensitive. 


GOVERNORS 


189 

\v     T«rViir»V» 


an 


~ 


06    * 


FIG.  t52; — -Mclntosh  &  Seymour  Diesel  govetoo? . 

a  spider  ^.  which  is  keyed  to  the  vertical  shaft  B  and  carries 
two  pins  to  which  are  fastened  the  two  weight  arms  C.  As 
the  shaft  rotates,  the  weights  tend  to  swing  outward,  being 


190 


OIL  ENGINES 


restrained  by  the  tension  of  the  two  springs.  One  end  of  the 
spring  is  pinned  to  the  weight  arm  while  the  other  end  is  held 
by  the  spring  collar  D  and  the  bolt  to  the  regulator  lever  G. 


No  Load  Position 

of  Eccentrics 
Zero  Pump  Stroke 


Half  Load  Position 

of  Eccentrics 
Half  Pump  Stroke 
=  X 


Full  Load  Position 

of  Eccentrics 
Max.  Pump  Stroke 
=  X 


er  of  F 


FIG.   153. — Mclntosh  &  Seymour  Diesel  eccentric  movements. 


The  lower  end  of  this  lever  rests  on  the  flat  collar  H,  which  also 
rotates  with  the  shaft.  The  thrust  of  the  collar  H,  due  to  the 
reaction  of  the  lever  G,  is  absorbed  by  the  spring  7.  A  regu- 
lator shaft  and  wheel  J  is  provided,  a  movement  of  which  alters 


GOVERNORS  191 

the  position  of  the  lever  K.  It  is  apparent  from  the  drawing 
that,  if  the  wheel  J  is  turned  to  lift  the  bearing  end  of  the  lever 
K,  the  thrust  of  the  spring,  through  the  ball-bearing  collar, 
will  be  less;  consequently  the  collar  H  is  raised,  throwing  the 
upper  end  of  the  lever  G  outward.  This  increases  the  tension 
on  the  governor  springs.  Through  the  control  of  the  weight 
arms  on  the  fuel  pump  the  engine  speed  will  increase.  If  this 
lever  K  moves  downward  placing  an  additional  thrust  on  the 
spring,  the  latter  will  be  compressed  a  further  amount.  This 
allows  H  to  move  downward  and,  in  turn,  lessens  the  governor 
spring  tension,  causing  the  engine  to  decrease  in  speed. 

The  eccentric  F  is  keyed  to  the  shaft  B  and  carries  a  second 
eccentric  E  which  is  linked  to  the  governor  weights.  This 
eccentric  E  drives  the  fuel  pump  plunger  through  the  eccentric 
strap  shown.  The  eccentric  F,  as  it  revolves,  carries  the  eccen- 
tric E,  which  is  held  by  the  equilibrium  of  the  weights  and 
springs,  with  it;  this  causes  the  pump  plunger  to  reciprocate, 
thus  delivering  a  fuel  charge  to  the  engine  cylinder. 

Figure  153  shows  the  relative  position  of  the  two  eccentrics 
when  at  rest.  Both  the  left-  and  right-hand  engines  have  the 
governor  shaft  turning  counter-clockwise,  as  viewed  from  the 
top.  As  the  engine  speeds  up,  the  weight  arms  pull  the  eccentric 
E  clockwise  in  relation  to  the  eccentric  F.  This  reduces  the 
combined  eccentricity  of  the  two  eccentrics,  which  action  de- 
creases the  pump  plunger  stroke. 

It  will  be  observed  that  this  acts  directly  on  the  pump  governor; 
this  places  a  considerable  reaction  on  the  governor  and  the 
weights  are  heavier  than  is  required  on  a  spilling  system  govern- 
ing device.  The  double  eccentric  design  assists  materially  in 
reducing  the  effort  required  to  produce  a  change  in  the  pump's 
stroke  at  a  change  in  speed.  The  regulation  is  as  close  as  occurs 
with  other  Diesels. 

Adjustments. — Since  two  springs  are  employed,  it  becomes 
necessary  to  adjust  the  springs  to  give  equal  'effect.  If  the 
weight-arm  positions  are  not  identical,  the  governor  will  be 
out  of  balance,  producing  erratic  speed  regulation.  To  equalize 
the  two  spring  tensions,  the  spring  collar  D  can  be  screwed  into 
one  of  the  springs  a  fractional  part  of  a  turn,  thereby  increasing 
the  tension  on  this  particular  spring. 

The  eccentrics  must  be  well  lubricated  to  reduce  the  wear 
occasioned  by  the  pump  reaction. 


192 


OIL  ENGINES 


The  weight  of  the  entire  governor  assembly  is  supported  by 
the  ball  bearing  A,  which  is  shown  in  Fig.  154.     This  bearing 


FIG.   154. — Governor  shaft  drive,  Mclntosh  &  Seymour  Diesel. 

also  receives  the  downward  thrust  of  the  upper  set  of  helical 


GOVERNORS 


193 


gears  D  and  E.  Precaution  must  be  taken  to  replace  any  broken 
balls,  and  all  wear  of  the  ball-race  must  be  taken  up  by  shimming 
under  the  case  which  is  supported  by  the  bracket.  If  the  bearing 
lowers,  the  upper  gear  train  will  not  mesh  properly.  This  pro- 
duces severe  cutting  of  the  gear  teeth  and  increases  the  side 
pressure  on  the  upper  bearing  G.  If  this  bearing  wears,  the  shaft 
is  thrown  out  of  plumb,  placing  a  side  pressure  on  the  lower 
bearing  F.  Since  this  bearing  F  is  rather  inaccessible,  the 
average  operator  neglects  to  inspect  it  for  wear.  . 


WEtGHTS 


FIG.   155. — Device  for  testing  governor  springs. 

General  Adjustments.  Governor  Springs. — It  is  impossible 
to  secure  satisfactory  functioning  of  a  governor  employing  two 
springs  unless  these  springs  are  of  the  same  diameter  wire  and 
have  the  same  number  of  coils  and  diameter  of  helix.  Even 
with  these  features  identical  in  two  springs,  the  spring  action 
may  vary  as  a  result  of  a  difference  in  the  heat  treatment.  In 
replacing  governor  springs  the  spring  should  be  checked.  A 

13 


194  OIL  ENGINES 

small  stand  and  weight  collar,  such  as  is  illustrated  in  Fig.  155, 
enables  the  engineer  to  observe  the  spring  action  under  compres- 
sion. Placing  the  spring  on  the  stand,  weights  are  added  to  the 
collar,  and  the  spring  compression  in  inches  noted  at  each  incre- 
ment of  weight.  Comparison  of  springs  then  becomes  a  simple 
matter.  The  weights  can  be  made  of  lead  rather  than  of  iron, 
thereby  reducing  the  size. 

Governor  Shaft  Gears. — Practically  all  the  Diesels  have  the 
governor  either  mounted  on  a  shaft  geared  to  the  engine  shaft 
or  are  driven  through  such  a  shaft.  On  the  vertical  engine 
the  governor  is  customarily  mounted  on  the  vertical  shaft  con- 
necting the  camshaft  to  the  engine  crankshaft.  This  involves 
the  use  of  a  set  of  gears  at  the  top  and  bottom  of  this  vertical 
shaft;  ordinarily  helical  gears  are  employed  since  the  gear 
diameters  can  be  kept  within  reasonable  limits.  Figure  154  out- 
lines the  gear  of  the  Mclntosh  &  Seymour  Diesel.  With  all 
helical  gears  there  is  a  thrust  in  the  direction  of  the  driven  shaft. 

Gear  Lubrication. — The  lubrication  of  the  governor-shaft  and 
lay  shaft  gears  is  of  vital  importance.  The  majority  of  engine 
builders  have  adopted  some  form  of  stream  lubrication.  If 
this  is  to  be  successful  in  keeping  down  gear-teeth  cutting,  the 
oil  must  be  fed  in  a  heavy  stream — it  is  useless  to  deposit  the  oil 
on  the  teeth  a  drop  at  a  time.  Much  of  the  oil  never  reaches 
the  pressure  line  between  the  two  contact  teeth  as  the  teeth 
squeeze  the  oil  film  out  the  sides  of  the  gears.  When  the  gears 
show  a  tendency  to  cut,  which  is  due  to  poor  lubrication  rather 
than  to  play  in  the  shaft  bearing,  the  sole  remedy  is  the  adoption 
of  an  oil  having  a  heavier  body.  This  oil  will  not  flow  off  the 
teeth  as  readily  as  does  the  standard  engine  oil. 


CHAPTER  XII 
AIR  COMPRESSION  SYSTEMS 

TYPES.     ADJUSTMENTS 

Air  Compression  Systems. — The  air  that  is  employed  in  in- 
jecting or  blowing  the  fuel  charge  into  the  engine  cylinder  must 
necessarily  be  at  a  high  pressure.  Since  the  force  that  produces 
the  flow  of  air  into  the  cylinder  against  the  resistance  of  the  fuel 
valve  atomizing  disks  is  the  difference  in  the  injection  air  pressure 
and  the  engine  compression  pressure,  it  is  evident  that  the  air 
pressure  must  be  above  the  compression  pressure  of  approxi- 
mately 500  Ibs.  To  insure  a  thorough  nebulization  of  the  oil 
and  a  rapid  rate  of  injection,  the  air  pressure  must  exceed  the 
value  by  several  hundred  pounds.  The  design  of  fuel  atomizer 
governs  the  required  air  pressure;  this  pressure  will  range  from 
1050  Ibs.  to  850  Ibs.  per  sq.  inch  at-  full  load. 

The  production  of  this  extremely  high  air  pressure  becomes 
one  of  the  serious  problems  of  Diesel  engine  construction  and 
operation.  The  ordinary  commercial  air  compressor  is  of  too 
light  a  design  to  guarantee  continuous  service;  consequently  all 
Diesels  are  equipped  with  compressors  that  have  been  developed 
especially  for  this  service.  While  a  few  of  the  first  Diesels  used 
a  single-stage  compressor,  all  modern  engines  have  either  a  three- 
or  two-stage  compressor.  The  air  temperature  due  to  a  final 
pressure  of  900  Ibs.  is  high  enough  to  ignite  the  lubricating  oil 
if  any  is  trapped  in  the  pipe  line.  To  overcome  this  as  well  as 
the  objection  of  having  a  large  diameter  compressor  cylinder 
exposed  to  this  high  pressure,  the  compression  is  divided  into 
stages  with  inter-coolers  placed  between  these  stages.  This  design 
places  but  a  small  pressure  on  the  low-pressure  cylinder  and 
allows  the  temperature  of  the  air,  after  leaving  each  stage,  to 
be  reduced  to  approximately  the  temperature  of  the  outside 
air.  The  high-pressure  discharge  temperature  is  then  around 
150°  Fahrenheit  rather  than  1500°  or  more  which  would  exist  with- 
out inter-  or  after-coolers.  Some  engineers  consider  that  this 
between-stage  cooling  reduces  the  power  consumption  of  the 
air  compressor.  Considering  the  same  volume  of  air  compressed 

195 


196 


OIL  ENGINES 


with  and  without  inter-cooling,  there  is  a  saving  from  inter- 
cooling.  However,  since  without  inter-cooling  either  the  discharge 
pressure  or  discharge  volume  will  be  greater  than  with  cooling,  a 
smaller  volume  of  air  could  be  compressed  under  non-cooling 
conditions  to  perform  the  same  degree  of  atomization.  The 
practical  advantages  of  inter-cooling  are  the  lessened  danger  of 
cylinder  fracture,  the  freedom  from  explosions  of  lubricating 
oil  that  might  collect  in  the  discharge  piping, 
and  the  better  service  obtained  from  the 
compressor  valves  while  working  under  a 
fairly  small  temperature  range. 

Compressor  Stages. — In  engines  ranging 
over  150  h.p.  capacity  it  is  customary  to 
employ  a  three-stage  compressor.  With 
the  smaller  units  a  two-stage  compressor 
is  more  generally  used.  The  volume  of 
air  required  for  these  smaller-powered 
engines  is  such  that  the  cooling  effect  of 
two  stages  and  one  inter-cooler  is  ample 
to  remove  the  objectionable  temperature 
conditions.  The  three-stage  compressor 
customarily  has  the  cylinders  placed  in- 
steeple  or  escalon,  wherein  the  high- 
pressure  cylinder  is  mounted  above  the 
low-pressure  cylinder  while  the  inter- 
mediate compression  space  is  between 
the  bottom  of  the  low-pressure  cylinder 
and  the  top  of  the  low-pressure  piston,  the 
latter  being  turned  with  a  barrel  smaller 
than  the  head,  as  is  outlined  in  Fig. 
156. 

Independent  Air  Compressors. — The  first  Diesels  manufac- 
tured in  the  United  States  were  equipped  with  belt-driven  three- 
stage  straight-line  air  compressors.  The  difficulties  experienced 
with  the  breaking  and  slipping  of  belts  resulted  in  the  adoption 
of  compressors  directly  connected  to  the  engine  crankshaft.  The 
independent  compressor  has  certain  features  that  are  of  advan- 
tage in  Diesel  practice.  If  two  compressor  units  are  installed 
with  independent  motor  drive,  either  belted  or  geared,  there  is 
no  danger  of  plant  shut-down  owing  to  compressor  trouble. 
Since  at  least  50  per  cent,  of  the  breaks  in  Diesel  operation  con- 


Fro. 


156.— Three-stage 
compressor. 


AIR  COMPRESSION  SYSTEMS  197 

tinuity  are  attributable  to  trouble  with  the  air  compressor  valve, 
it  must  be  conceded  that  any  system  that  will  enable  the  engine 
to  continue  functioning  in  the  face  of  a  broken  air  compressor 
valve  ought  to  be  welcomed.  In  a  number  of  plants  where  a 
modern  Diesel  with  direct-connected  compressor  is  installed  by 
the  side  of  an  old  Diesel  with  an  independent  motor-driven  com- 
pressor, it  is  quite  common  to  see  the  engineer  start  up  the  inde- 
pendent compressor  to  relieve  the  engine  compressor  because  of 
a  faulty  valve.  Without  the  independent  compressor  such  a 
plant  would  be  helpless  in  case  of  accident,  if,  as  is  usual,  the 
plant  load  is  so  large  that  it  cannot  be  handled  with  one  engine 
disabled.  For  these  reasons,  each  plant  should  possess  one 
motor-driven  compressor  of  a  capacity  sufficient  to  handle  the 
largest  engine  installed  in  the  plant  even  though  the  engines  have 
built-in  compressors. 

Built-in  Compressors. — As  has  been  heretofore  mentioned, 
all  the  modern  Diesels  have  the  air  compressor  built  onto  the 
engine  frame,  being  driven  by  a  crank  on  the  end  of  the  crank- 
shaft. As  previously  outlined,  this  has  the  objection  of  entailing 
an  engine  shut-down  in  case  of  compressor  failure.  On  the  other 
hand,  the  direct-connected  unit  simplifies  the  plant  install  tion 
and  brings  this  important  auxiliary  under  the  eyes  of  the  engine 
operator.  This  insures  a  better  lubrication  treatment  and  places 
the  compressor  in  a  light,  dustless  location.  Moreover,  this 
design  entails  the  employment  of  a  minimum  amount  of  pipe. 
Engines  having  the  closed-nozzle  fuel  injection  valve  are  ordi- 
narily provided  with  air  bottles  in  which  is  stored  an  excess  sup- 
ply of  air.  These  engines  can  be  satisfactorily  charged  from  a 
separate  compressor  unit.  The  engines  employing  the  open- 
nozzle  valve  seldom  have  air  bottles;  the  air  enters  the  atomizer 
direct  from  the  compressor.  With  these  engines,  before  an 
independent  compressor  can  be  used,  some  manner  of  air  bottle 
must  be  added  to  the  equipment  since  the  independent  com- 
pressor never  runs  at  engine  speed. 

Beyond  these,  there  are  no  other  advantages  in  the  direct- 
connected  compressor  for  stationary  engines.  With  engines 
of  variable  speed,  such  as  marine  engines,  the  built-in  compressor 
is  essential  if  maximum  economy  is  to  be  secured.  On  slow 
speed  the  amount  of  air  needed  at  the  injection  valve  is  less 
than  on  full  speed,  the  ratio  being  approximately  identical 
with  the  ratio  in  speed  change.  If  an  independent  compressor 


198 


OIL  ENGINES 


charged  the  engine,  at  slow  speed  an  excess  amount  of  air  would 
be  compressed  and  ultimately  lost  through  the  relief  valve. 
Since  the  direct-connected  compressor  operates  at  engine  speed, 
the  rate  of  compression  output  is  the  same  as  the  rate  of  demand. 
Busch-Sulzer  Diesel  Air  Compressor. — A  three-stage  air 
compressor  is  incorporated  in  the  design  of  the  Busch-Sulzer 
Class  B  engine.  The  compressor  cylinder  assembly  is  bolted 


.Ground  Seats 
Material  Steel    Finish  all  over 


FIG.   157. — Busch-Sulzer  Diesel  air  compressor  valve. 

to  the  engine  frame,  giving  the  appearance  of  a  fifth  cylinder. 
The  low-pressure  cylinder  casting  is  bolted  to  the  frame  with  the 
high-pressure  cylinder  above  it  while  the  intermediate  cylinder 
is  formed  by  the  stepped  piston,  being  between  the  piston  barrel 
and  the  low-pressure  cylinder  walls.  All  the  valves  are  similar 
to  the  high-pressure  suction  valve  shown  in  Fig.  157.  These 
valves  are  of  the  flat-seated  poppet  type  and  are  made  of  alloy 
steel.  The  operator  of  this  engine  should  keep  on  hand  a  com- 
plete set  of  spare  valves  since  they  frequently  break  at  the  point 
6,  Fig.  157.  There  is  serious  question  as  to  the  under- 


AIR  COMPRESSION  SYSTEMS 


199 


lying  cause  of  this  valve  fracture;  it  is  probably  due  to  too  great 
a  valve  lift,  resulting  in  hammer  blows  as  the  valve  falls  back 
on  its  seat. 

With  this  air  compressor  is  furnished  three  air  bottles — two 
for  storage  and  one  for  the  starting  air.  The  air  is  cooled  both 
between  stages  and  after  passing  the  high-pressure  discharge 
valve.  The  cooling  is  effected  by  copper  coils  placed  in  the  top 
of  the  compressor  jacket  and  surrounding  the  high-pressure 
cylinder. 


(  Valves,  Del.  Suction 
}  Eic.,  Similarto  -. 
\LH.Engine. 


LfiDel.  Valves. 
LPDel.        I 


..•1.  P.  Suction 


..-;.?  L.P.SuctionValyes 


K .-.-j-2--.  *.~3'8f'foC.L. 

tTQftlt&bcrfT 

FIG.   158. — Mclntosh  &  Seymour  marine  Diesel  air  compressor. 

Air  Pressure  Regulation. — To  give  a  variable  air  discharge 
pressure  dependent  on  the  engine  load,  the  suction  of  the 
low-pressure  cylinder  has  a  damper  under  control  of  the  engine 
governor.  On  low  loads  the  movement  of  the  governor  sleeve 
partially  closes  the  suction  opening.  This  results  in  a  low  air 
discharge  pressure.  To  the  discharge  of  the  low-pressure  cyl- 
inder is  connected  the  servomotor  which  controls  the  fuel  valve 
opening  and  closing  points.  As  the  air  suction  is  throttled, 
lowering  the  low-pressure  cylinder  terminal  pressure,  the  servo- 
motor piston  moves  under  the  influence  of  a  spring  which 
overcomes  the  lessened  air  pressure  on  the  opposite  side  of  the 
servomotor  piston  making  the  fuel  valve  open  late  and  close  early. 

Mclntosh  &  Seymour  Marine  Diesel  Air  Compressor. — • 
Figure  158  outlines  the  compressor  of  the  Mclntosh  &  Seymour 


200  OIL  ENGINES 

Marine  Diesel.  The  compressor  is  three  stage  and  is  placed 
at  the  front  end  of  the  engine,  being  driven  by  an  overhung  crank 
on  the  engine  shaft.  The  low-pressure  and  intermediate  cyl- 
inders are  cast  together  as  shown  in  Fig.  158,  while  the  high- 
pressure  cylinder  is  in  one  piece  with  the  low-pressure  cylinder 
head.  The  low-pressure  suction  and  discharge  valves  are  all  in 
the  low-pressure  cylinder  head ;  the  intermediate-pressure  valves 
are  arranged  around  the  cylinder  barrel  and  the  high-pressure 
valves  are  in  the  high-pressure  cylinder  head.  The  air,  after 
leaving  the  low-pressure  cylinder,  enters  the  low-pressure  cooler. 
This  is  a  steel  tank  in  which  the  air  circulates,  while  the  cooling 
water  flows  through  copper  coils.  This  allows  the  moisture 
in  the  air  to  condense  and  rest  at  the  bottom  of  the  tank;  the 
plan  is  superior  to  that  one  where  the  air  is  in  the  coils  since  with 
the  latter  there  is  a  decided  tendency  on  the  part  of  the  air  to 
hold  the  moisture  in  suspension.  The  intermediate-pressure  and 
the  high-pressure  discharge  air  lines  enter  a  common  tank 
where  the  air  currents  circulate  in  separate  coils  of  copper  while 
the  cooling  water  is  flowing  around  the  coils.  This  plan  of  using 
a  common  cooling  tank  has  the  advantage  of  reducing  weight, 
but,  even  though  it  is  quite  usual  to  so  design  the  coolers,  there 
is  some  question  about  the  efficiency  of  the  cooling  system. 

The  air  compressor  is  supplied  with  a  pressure  and  volume 
Regulator.  This  appears  in  Fig.  158  together  with  the  control 
rod  and  indicator.  This  regulator  is  a  cylinder  connected  to 
the  low-pressure  air  cylinder  and  contains  a  piston  that  is  raised 
and  lowered  by  the  control  rod  acting  through  the  gears  at  the 
top  of  the  regulator.  By  the  proper  displacement  of  this  piston 
the  low-pressure  cylinder  volume  is  altered  to  give  any  desired 
high-pressure  discharge  pressures  The  indicator  scale  on  the 
handwheel  shaft  is  marked  with  the  same  load  points  as  is  the 
fuel  control  lever.  The  operator,  then,  on  throwing  the  fuel 
injection  control  to  full  load  moves  the  air  indicator  to  the 
corresponding  point.  This  gives  maximum  air  pressure  for  a 
maximum  fuel  charge. 

The  compressor  valves  closely  follow  the  design  appearing 
Fig.  157.  The  material  is  a  nickel-steel  alloy  heat-treated  and 
toughened.  A  valve  lift  of  .03  inch  is  about  the  most  advisable 
value  to  use. 

Mclntosh  &  Seymour  Stationary  Diesel  Air  Compressor. — 
The  stationary  engine's  compressor  is  practically  the  same  as  the 


AIR  COMPRESSION  SYSTEMS  201 

compressor  of  the  marine  engine,  though  the  regulator  is  not 
included. 

The  chief  points  of  attention  are  the  valves  and  the  connect- 
ing-rod boxes.  The  former  frequently  break  at  the  junction 
of  the  "brim  and  crown."  This  is  usually  attributed  to  an 
excessive  lift  of  the  valve  and  can  only  be  avoided  by  valve 
replacement  when  the  lift  becomes  more  than  .05  inch.  To 
avoid  air  leakage  the  valve  seats  must  be  well-nigh  perfect. 
To  regrind  a  valve  only  a  small  amount  of  powdered  glass  and 
vaseline  should  be  used.  The  slightest  scratch  on  the  seat  sur- 
face will  destroy  the  valve's  usefulness. 

The  connecting-rod  brasses  require  attention  more  than  do  the 
main  engine  rods.  The  current  of  air  passing  through  the 
compressor  frame  deposits  dirt  and  grit  on  the  bearings  that  soon 
reveal  their  presence  by  overheating. 

The  control  of  the  air  pressure  is  attained  by  the  regulation  of 
the  valve  leading  to  the  starting  tank;  opening  this  allows  part 
of  the  air  compressed  to  enter  this  tank,  lowering  the  pressure 
in  the  line  to  the  fuel  pump.  Two  running  air  tanks  and, one 
starting  tank  are  supplied  for  each  engine, 


FIG.   159. — Snow  Diesel  three-stage  air-compressor. 

Snow  Diesel  Air  Compressor. — The  Snow  Diesel  is  equipped 
with  a  three-stage  compressor,  the  piston  being  of  the  stepped 
type,  although  the  smaller  units  are  fitted  with  two-stage  com- 
pressors. The  three-stage  unit  cross-section  appears  in  Fig.  159. 
The  valves  are  of  the  flat  feather  type,  which  are  of  light  steel 
strips  restrained  at  the  ends  and  free  to  lift  from  the  seat  to  allow 
the  air  to  pass.  This  valve  design  permits  the  valve  to  seat  fairly 
gently  without  danger  of  fracture  due  to  hammering;  the  frac- 


202 


OIL  ENGINES 


tures  that  do  appear  are  caused  by  t 'fatigue,"  resulting  from  con- 
tinual bending  of  the  steel  fibres. 

The  compressor  is  arranged  with  inter-coolers  between  the 
stages.  These  are  formed  in  the  cylinder  jackets.  The  high- 
pressure  discharge  passes  through  a  cooling  coil  placed  in  the 
high-pressure  cylinder  cover. 

Pressure  control  is  obtained  by  altering  the  low-pressure  suc- 
tion area  through  the  hand  lever  a. 


Cooling  Water  Inlet 


•       FIG.   160. — McEwen  Diesel  air  compressor. 

McEwen  Diesel  Air  Compressor. — On  the  small-  and  medium- 
powered  McEwen  Diesel  engines  a  two-stage  compressor  is 
mounted  on  the  side  of  the  engine  frame,  Fig.  160.  This  stepped 
piston  is  driven  by  a  crank  on  the  end  of  the  engine  shaft.  The 
valves  are  of  the  standard  "plug  hat"  form.  The  two  cylinders 
are  water-jacketed,  and  the  inter-cooler  and  after-cooler  coils,  of 
copper  tubing,  are  placed  in  the  high-pressure  cylinder  jacket. 
The  air,  after  leaving  .the  low-pressure  discharge  at  a,  passes 
through  an  oil  separator  before  entering  the  inter-cooler  coils  at  6. 
After  being  cooled,  the  air  issues  from  the  coil  at  c  and  enters  the 
high-pressure  cylinder  through  the  high-pressure  suction  valve  d. 
After  being  compressed,  it  is  forced  out  the  discharge  valve  at  e 
into  the  after-cooler  coils  at/.  It  leaves  these  coils  at  g  and  flows 
to  the  fuel  valve. 


AIR  COMPRESSION  SYSTEMS 


203 


Pressure  control  is  achieved  by  regulating  the  suction  opening 
at  h.  The  valve  lifts  should  be  between  .03  and  .04  inch. 

No  air  tank  is  interposed  between  the  compressor  and  the  fuel 
valve;  consequently  the  air  charge  for  both  compression  stro.kes 
of  the  air  compressor  enters  the  fuel  nozzle  on  the  power  stroke  of 
the  engine.  The  air  line  is  of  some  volume;  therefore  the  drop 
in  the  discharge  air-line  pressure  at  the  point  of  injection  valve 
opening  is  but  slight. 

National  Transit  Diesel  Air  Compressor. — The  National  Tran- 
sit Diesel  has  a  two-stage  compressor  bolted  to  the  engine  frame, 
the  piston  being  stepped,  and  driven  by  a  crank  on  the  end 
of  the  engine-shaft.  The  two  cylinders  and  the  valve-cavity 
covers  are  water-cooled;  an  inter-receiver  between  the  two  cyl- 
inders serves  as  an  inter-cooler  as  well.  Regulation  is  obtained 
by  hand  control  of  the  suction  opening. 


X  =  Max.  Stroke 


Bypass  Air  Line 
from  Low  Pressure 
Discharge 

(\      . 

- 

Air  Line  to  High 
Pressure  Suction 

I 

FIG.  161. — Standard   Fuel   Oil  engine  injection  air  pressure   control. 

Standard  Fuel  Oil  Diesel  Air  Compressor. — A  two-stage  com- 
pressor is  driven  by  a  crank  off  the  engine  crankshaft,  Fig. 
98.  While  the  compressor  is  only  two-stage,  it  has  a  three-stage 
effect.  The  air  is  compressed  in  the  scavenging  cylinder  of  the 
engine  to  from  7  to  1 1  pounds  gage.  It  then  passes  into  a  receiver 
from  where  it  is  blown  into  the  engine  working  cylinder  during 
the  exhaust  portion  of  the  cycle.  The  suction  of  the  low- 
pressure  air-compressor  cylinder  is  connected  to  this  scaveng- 


204  OIL  ENGINES 

ing  air  receiver;  consequently  the  low-pressure  cylinder  is  in 
effect  an  intermediate  cylinder. 

The  discharge  from  the  low-pressure  cylinder  is  piped  to  the 
starting  air  tanks.  A  connection  on  this  line  leads  to  the  pres- 
sure control,  Fig.  161.  The  air  enters  the  control  body  at  a. 
The  plunger  is  under  the  control  of  the  engine  governor,  altering 
its  stroke  according  to  the  load  carried.  As  the  plunger  moves 
to  the  right,  the  port  6  is  uncovered,  and  the  air  flows  through  the 
port  b  back  to  the  suction  of  the  high-pressure  cylinder  of  the 
air  compressor  where  it  is  further  compressed  to  about  900  pounds. 
From  the  high-pressure  discharge  the  air  is  forced  into  the  fuel 
valve. 

It  is  apparent  that,  with  the  larger  volume  to  be  compressed, 
the  final  pressure  at  the  fuel  valve  is  high,  as  is  desirable,  at  full 
load.  On  lower  loads  the  plunger  uncovers  less  of  b,  allowing  a 
corresponding  smaller  amount  of  air  to  enter  the  high-pressure 
cylinder,  reducing  the  injection  pressure.  This  injection  control 
is  very  close  in  regulation;  a  hand  adjustment  allows  any  desired 
pressure  to  be  secured  at  any  set  governor  position. 

At  first  glance,  this  seems  to  involve  a  considerable  air-com- 
pression loss.  However,  all  air  that  is  not  used  in  the  high- 
pressure  air-compressor  cylinder  enters  these  starting  tanks. 
A  relief  valve  permits  the  excess  above  the  capacity  of  the  tanks 
to  pass  into  the  scavenging  tank,  the  valve  being  set  to  lift  at  a 
pressure  of  from  100  to  140  Ibs.  per  sq.  inch.  This  reduces,  to 
some  extent,  the  compressor  losses,  which  are  by  no  means  high. 

Allis -Chalmers  Diesel  Air  Compressor. — The  14-  and  16-inch 
stroke  Allis-Chalmers  Diesels  employ  a  two-stage  air  compressor, 
while  the  18-inch  stroke  units  have  three-stage  compressors. 
The  designs  of  the  two-  and  three-stage  compressors  follow 
the  same  general  lines.  These  units  differ  from  most  Diesel 
compressors  in  that  the  inter-coolers  are  not  placed  in  the  high- 
pressure  cylinder  head  jacket.  Each  cooling  coil  is  placed  in  a 
cavity  in  the  base  of  the  compressor  casting,  which  is  in  the  form 
of  a  cast-iron  drum.  The  air  from  the  low-pressure  discharge 
enters  an  air  pot  or  receiver;  a  copper  pipe  is  coiled  about  the  pot 
and  is  connected  to  it.  Both  coil  and  pot  fit  into  the  cooling 
drum.  In  Fig.  12  the  compressor  is  shown  in  position  on  the 
engine  frame.  On  the  two-stage  compressor  the  air,  after  passing 
through  the  inter-cooler  coil  and  pot,  is  compressed  in  the  high- 
pressure  cylinder;  the  air  is  then  discharged  into  the  after-cooler 


AIR  COMPRESSION  SYSTEMS 


205 


air  coils  which  are  placed  in  the  after-cooler  water  pot.  On  the 
three-stage  compressors  two  inter-coolers  are  used.  The  valve 
and  cage  appear  in  Fig.  162. 


VALVE 


VALVE   SEAT 


FIG.  162.- 


VALVE  .CAP 

-Allis-Chalmers  Diesel  air-compressor  valve. 


Compressor  Valves. — The  engineer  should  early  recognize  the 
serious  part  the  air  compressor  and  its  valves  play  in  the  success- 
ful operation  of  the  engine.  The  compressor  must  function 
continuously  and  perfectly.  To  attain  this,  the  air  valves 
must  be  kept  in  first-class  condition.  The  least  amount  of  wear 
destroys  their  usefulness.  The  lift  of  the  valve  should  be  as 
small  as  is  possible  while  maintaining  a  full  air  opening.  If 
an  excessive  lift  is  allowed,  the  valve  will  hammer  on  its  seat, 
damaging  both  valve  and  seat.  Often  compressors  are  dis- 
covered emitting  a  sharp  click  as  the  valves  seat,  with  the  opera- 
tor perfectly  satisfied  with  the  engine's  performance.  Usually 


206  OIL  ENGINES 

a  week  of  continuous  operation  ruins  such  valves.  In  regrinding 
all  types  of  poppet  valves,  a  very  meager  amount  of  powdered 
glass  and  vaseline  is  used.  The  valve  should  be  rotated  very 
lightly,  with  no  pressure  exerted  on  it  and  the  valve  cage. 
After  grinding,  all  parts  must  be  thoroughly  washed  with  kero- 
sene or  gasolene.  A  defective  valve  reveals  itself  in  the  change 
in  the  air  pressure. 

Air  Suction. — If  the  plant  is  at  all  dusty,  an  air  pipe  with  the 
free  end  covered  by  a  fine  mesh  screen  should  be  run  from  out- 
side of  the  building.  If  this  is  not  possible,  the  suction  connec- 
tion at  the  compressor  should  be  screened  with  a  fine-mesh 
netting,  covered  with  muslin.  The  dust  will  collect  on  the 
screen,  and  the  engineer  need  not  be  informed  that  he  must  clean 
this  screen  at  least  once  a  week. 

Air -compressor  Lubrication.  —  This  will  be  more  fully  dis- 
cussed in  the  chapter  on  Lubrication.  The  engineer  is  quite 
safe  in  following  factory  instructions  as  to  the  amount  of  cylinder 
lubrication  he  should  use.  It  is  not  advisable  to  increase  the 
amount  recommended,  since  any  oil  that  is  not  destroyed  in  the 
cylinder  will  collect  in  the  air  piping.  This  oil  deposit  will  quite 
likely  explode,  especially  if  the  air  temperature  is  not  maintained 
below  150°.  As  a  safeguard,  the  discharge  line  should  be 
equipped  with  an  oil  separator  and  relief  valve.  The  latter  is 
absolutely  necessary.  A  precaution  that  can  well  be  observed  in 
every  plant  is  the  daily  purging  of  the  air  line  and  bottles  of  all 
collected  oil  and  moisture. 

Air  Pipe. — All  manufacturers  supply  air  piping  of  ample 
strength.  Occasionally  on  second-hand,  or  rearranged,  installa- 
tions new  lines  are  erected.  It  is  never  advisable  to  use  steel 
pipe  less  than  double  extra  heavy,  though  copper  pipe  is  far  better. 
The  fittings  should  be  of  ground-joint,  gasketless  design;  not 
only  should  the  pipe  be  screwed  into  the  fitting  flanges,  but 
the  latter  should  have  set-screws  locking  them  to  the  pipe. 
Some  plants  use  a  Van-Stone  joint  or  a  welded  connection.  These 
are  excellent  but  are  ordinarily  impossible  to  obtain  for  a  small 
line.  The  pipe  line  is  best  run  with  the  smallest  possible  number 
of  fittings  since  each  is  a  potential  source  of  trouble. 

Air  Bottles. — The  typical  air  receiver  or  bottle  is  made  of 
steel  with  all  joints  welded.  It  is  always  advisable  to  have  a 
drip  cock  or  plug  at  the  base  of  each  bottle  to  draw  off  the  mois- 
ture occasionally.  It  is  usual  to  carry  the  air  pressure  at  approxi- 


AIR  COMPRESSION  SYSTEMS 


207 


mately  1000  pounds,  though  this  varies  with  the  load  conditions. 
In  operating,  one  bottle  should  be  used  for  starting  purposes 
only,  and,  after  charging  to  about  1000  Ibs.  per  sq.  inch,  this 
bottle  is  cut  off  from  the  air  line  by  closing  its  needle  valve.  Of 
the  other  two,  if  only  three  are  supplied  with  the  engine,  it  is 
good  practice  to  carry  one  fully  charged  while  allowing  the  other 
to  float  on  the  air  line.  With  this  arrangement,  in  case  of  a 
failure  of  the  air  line,  a  starting  and  a  running  bottle  are  on  hand 
fully  charged. 

The  open-nozzle  engines  are  not  equipped  with  air  bottles, 
since  the  air  passes  directly  to  the  injection  valve.  For  starting 
purposes  one  or  more  steel  tanks  are  employed,  the  air  being 
around  200  to  250  Ibs.  per  sq.  inch.  To  charge,  the  excess  air 
from  the  compressor  is  piped  to  the  tanks.  An  engineer  should 
always  charge  these  tanks  promptly  after  starting  the  engine. 
Many  Diesels  have  been  condemned  as  unsatisfactory  in  opera- 
tion when  the  fault  was  attributable  to  the  engineer's  carelessness 
in  failing  to  have  the  air  tanks  fully  charged. 


STB 

/ 

<7D 

X 

C 

/ 

? 

JjfcO 

<cc 

/ 

x 

/ 

c 
o 

X 

r 

P 

• 

0         10         20        30        40         50        00        70        60        90        100       1) 
Per  Cent,  of  'Full    Load 

FIG.   163. — Injection-air  pressure. 

Injection -air  Pressure.  — Each  design  of  fuel  atomizer  re- 
quires a  certain  air  pressure  to  properly  inject  the  oil.  This 
pressure  will  vary  with  the  resistance  or  "braking"  action  of 
the  atomizer  disks.  It  follows  that  no  set  pressure  values  can 
be  given  which  will  apply  to  all  engines.  However,  the  curve  in 
Fig.  163  gives  the  relation  between  engine  load  and  injection 
pressure  that  is  correct  for  practically  all  closed-nozzle  engines. 
For  open-nozzle  units  the  pressure  will  run  some  50  to  100 
pounds  lower  than  is  given  in  the  table. 


208  OIL  ENGINES 

The  engineer  should  recognize  that  on  light  loads  the  injection 
pressure  must  be  lower  than  is  required  on  full  load.  If  the 
pressure  is  not  reduced,  the  air  will  "slug"  the  oil  into  the  cylin- 
der since  there  is  practically  no  atomizer  resistance.  The 
engine  will  then  smoke  badly.  Conversely,  with  full-load  fuel 
charges  a  low  air  pressure  will  not  be  sufficient  to  force  the  large 
oil  charge  through  the  disks.  Still  another  condition  necessi- 
tates higher  pressure  on  full  load.  When  the  engine  is  carrying 
a  heavy  load,  the  cylinder  heats  up,  causing  the  fresh  charge  of 
air  in  the  engine  cylinder  to  have  a  higher  terminal  pressure 
resulting  from  the  increased  absorption  of  heat.  To  obtain  a 
given  pressure  drop  in  the  atomizer,  the  air  injection  pressure 
must  be  increased. 


CHAPTER  XIII 


COOLING  SYSTEMS 

TYPES  OF  SYSTEMS.     PUMPS.     WATER  PURIFICATION 

Distribution  of  Heat  Losses. — Various  experiments  on  the 
subject  of  Diesel  heat  losses  check  very  closely  as  to  final  results. 
The  consensus  of  opinion  is  that  the  total  heat  evolved  in  the 
combustion  of  a  charge  of  oil  in  the  engine  cylinder  is  absorbed 
in  doing  work  and  in  various  losses  in  the  engine  at  the  following 
percentages: 

Heat  generated  in  the  cylinder 100 

Heat  converted  into  work 30 

Heat  lost  in  engine  friction 6 

Heat  lost  in  the  exhaust  gases 28 

Heat  absorbed  by  the  cooling  water 34 

Heat  lost  by  radiation,  etc 2 


100 


40 


20 


Per  Cent 


Per  Cent 


Per  Cent 


Compress 


Converted   into  useful  Work 


Absorbed 


by  Cooling  Water 


Lost  in  Exhaust,  Kadialion.Friction     and  Air 


50 
Per  Cent  Load 


75 


.100 


FIG.   164. — Heat  distribution  in  Diesel  engines. 


Figure  164  covers  the  losses  at  various  loads.  These  values  are 
the  result  of  a  number  of  experiments  on  various  engines.  If 
the  work  done  is  30  per  cent,  of  the  heat  generated,  then  the  engine 
will  consume  8470  B.t.u.  per  b.h.p.  The  cooling  water  must 
be  of  a  quantity  sufficient  to  absorb  34  per  cent,  of  the  amount 
or  2879  B.t.u.,  in  round  numbers  3000  B.t.u.  per  hour. 

209 

H 


210  OIL  ENGINES 

Cooling  Water  Required.  —  The  calculations  necessary  to  em- 
ploy in  determining  the  amount  of  cooling  water  required  for  a 
Diesel  are  quite  simple.  As  an  example  of  the  maximum  amount 
that  could  be  used,  the  intake  water  temperature  at  the  jacket 
entrance  can  be  taken  as  90°.  This  is  at  least  10°  higher  than 
normal,  even  with  a  cooling  pond.  The  engine  discharge  water 
temperature  can  be  taken  as  140°  Fahrenheit,  which  is  20°  below 
the  value  most  successfully  used.  Then  the  rise  in  temperature 
will  be  50°;  consequently  each  pound  of  water  will  absorb  50 
B.t.u.  The  water  per  h.p.  hour  will  be 


This  expressed  in  the  form  of  an  equation  appears  as 


100(^1-  fe) 
where 

W  =  weight  of  water  required  per  h.p.  hour. 
X  =  percentage  of  heat  absorbed  by  the  water. 
H   =  total  heat  supplied  to  the  engine. 
ti   =  discharge  water  temperature  deg.  Fahr. 
tz   =  intake  water  temperature  deg.  Fahr. 

The  inlet  and  discharge  temperatures  given  may  not  check  with 
those  observed  in  any  particular  installation,  nevertheless  the 
temperature  range  is  approximately  correct;  it  is  this  factor  that 
is  important.  Table  I  gives  the  temperatures  and  quantities 
of  water  passing  through  Diesel  engines.  This  table  is  the  result 
of  a  test  on  three  Mclntosh  &  Seymour  500  h.p.  Diesels  in- 
stalled by  the  Texas  Light  and  Power  Co.  at  Paris,  Texas.  Since 
these  engines  were  developing  close  to  500  h.p.  each,  this  value 
may  well  be  assumed  in  computing  the  water  rate  per  b.h.p. 
With  this  assumption  the  Water  per  b.h.p.  per  minute  was 
I2%oo  Ibs.  or  75  Ibs.  per  b.h.p.  per  hour.  This  considerably  ex- 
ceeded the  value  computed  above,  which  can  be  explained  on 
the  grounds  that  both  the  exhaust  head  and  air  compressor  were 
maintained  at  a  very  low  temperature.  In  ordinary  operation 
these  engines  tested  do  not  carry  the  exhaust  header  tempera- 
ture lower  than  130  to  135°  Fahrenheit. 

The  cooling  system  should  then  be  based  on  a  pumping  and 
cooling  tower  capacity  of  at  least  60  Ibs.  per  b.h.'p.  per  hour  of 
installed  engine  rating. 


COOLING  SYSTEMS 


211 


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212 


OIL  ENGINES 


Types  of  Cooling  Systems.  Closed  System. — Two  designs 
of  cooling  systems  are  in  quite  general  use.  Figure  165  outlines 
the  closed  system  often  found  in  small  installations.  With  this 
design  the  water  from  the  engine  jacket  is  discharged  through  a 
distributing  pipe  D  on  a  cooling  tower  C.  The  water  drips  down 
through  the  tower  and  is  stored  in  the  sump  A,  from  which  point 
it  is  drawn  by  the  circulating  pump  B  and  forced  through  the 
engine  jacket  and  out  the  discharge  again.  When  this  system  is 
adapted  to  a  horizontal  engine,  the  discharge  line  should  rise 


FIG.  165. — "Closed"  cooling  water  system. 

vertically  from  the  engine  until  it  is  above  the  cooling  tower  dis- 
tributing pipe.  With  such  a  layout  it  is  necessary  to  place  a 
vent  pipe  in  the  discharge  line,  immediately  above  the  engine. 
This  prevents  the  formation  of  steam  or  air  pockets  in  the  jacket 
with  consequent  overheating  of  the  cylinder. 

While  the  figure  embodies  a  centrifugal  circulating  sump,  this 
design  of  pump  is  one  that  should  never  be  employed  with  a 
closed  system.  The  objection  to  this  pump  is  based  on  the 
liability  of  losing  the  suction.  This  is  of  frequent  occurrence 
when  the  drive  belt  becomes  dirty  or  oily,  and  in  the  best-kept 
plants  a  belt  at  times  breaks. 

There  is  a  serious  objection  to  the  closed  system  that  makes  its 
use  inadvisable  under  any  condition  with  a  Diesel  engine.  The 
discharge,  being  closed,  is  not  under  the  observation  of  the  opera- 
tor. The  circulation  can  be  broken  without  the  knowledge  of 


COOLING  SYSTEMS 


213 


the  operating  force;  this  has  resulted  in  broken  cylinder  heads 
and  jackets  in  a  number  of  cases.  As  a  safeguard,  a  check  valve 
with  an  outside  lever  connected  to  a  bell-ringer  is  recommended. 
Open  Cooling  System. — Figure  166  is  the  schematic  layout  of 
the  open  cooling  system  with  a  storage  tank.  With  this  system, 
the  water  is  stored  in  the  overhead  tank  and  enters  the  cylinder 
jacket  at  A;  after  cooling  the  engine,  the  water  discharges  into 
the  open  funnel  at  B,  flowing  into  the  sump  C.  A  centrifugal 
pump  D  lifts  the  water  from  this  sump  and  discharges  it  in  the 


Q 


FIG.  166. — Open  cooling  system  with  overhead  tank. 

top  of  the  cooling  tower  E.  In  dripping  down  this  tower  the  water 
is  cooled  and,  collecting  in  the  catch  basin  F,  is  lifted  by  the  pump 
G  and  forced  into  the  overhead  tower.  This  system  is  frequently 
used  without  the  overhead  tank.  With  this  plan  the  pump  G 
forces  the  water  through  the  engine  jacket.  It  is  at  once  appar- 
ent that  this  latter  plan  is  objectionable  since  it  is  dependent  on 
the  pump  G  for  the  steady  flow  of  water.  If  the  suction  is  de- 
stroyed, the  system  at  once  becomes  dangerous.  Low-pressure 
engines  are  often  installed  with  this  system,  but  the  cost  of  a 
Diesel  plant  is  entirely  too  great  to  ignore  the  overhead  tank. 
A  30,000-gallon  tank  with  a  30-foot  steel  tower  can  be  installed 
at  a  pre-war  cost  of  approximately  $3000.  The  interest  on  the 
investment  ($180)  is  a  low  premium  on  the  insurance  of  protection 
against  engine  damage  due  to  lack  of  cooling  water. 

With  a  few  engines  the  cooling  water,  after  passing  through  the 
engine,  is  used  to  cool  the  exhaust  header.     With  others  the  water 


214  OIL  ENGINES 

is  first  passed  around  the  air  compressor  and  inter-  and  after-cooler 
before  entering  the  engine  jackets.  Results  from  these  cooling 
methods  are  fairly  satisfactory.  The  proper  cooling  pipe  layout 
embodies  individual  lines  to  the  air  compressor  and  coolers, 
to  each  engine  cylinder  jacket,  to  the  valve  cages  and  to  the  ex- 
haust headers.  All  these  lines  should  have  brass  cocks  in  the 
intake  side,  and  the  discharges  should  all  lead  to  a  common 
discharge  funnel.  Each  discharge  line  may  well  be  fitted  with 
thermometers,  while  a  single  thermometer  on  the  intake  line 
before  the  lines  branch  to  the  various  parts  is  sufficient. 

Water  Pipe. — All  the  water  lines  in  the  engine  room  are  best 
laid  in  pipe  chases.     This  places  the  piping  out  of  sight  and 
provides  more  room  in  the  plant.     The  pipe  should  be  extra 
heavy  galvanized  pipe;  though  the  pressure  is  small,  this  thick- 
ness of  pipe  prolongs  the  life  of  the  system.     The  threads  in  all 
fittings  must  be  clean  and  sharp,  while  the  pipe  ends  should  be 
fully  threaded.     Red  lead  or  other  dope  must  be  avoided,  while 
the  unions  should  have  either  ground  joints  or  copper  gaskets; 
rubber  gaskets  are  at  best  of  short  life,  and  a  pipe  line  should  be 
made  up  in  such  a  way  that  it  will  never  give  trouble.     In 
those  engines  where  water  is  admitted  direct  into  the  exhaust 
pipe,  the  drip  line  from  the  exhaust  should  not  discharge  into 
the   cooling-water  discharge;  due  to  the  carbon  in  suspension, 
it  is  advisable  to  run  this  drip  to  the  sewer.     Frequently  the  fuel 
contains  enough  sulphur  to  eat  iron  pipe  if  employed  in  the 
drip  line;  consequently  brass  drips  can  be  more  profitably  used. 
Cooling  Towers  and  Tanks. — As  has  been  already  explained, 
an  overhead  tank  is  advisable  in  every  Diesel  installation.     A 
steel  tower  and  tank  of  from  25,000  to  30,000  gallons  capacity 
is  sufficient  for  any  installation  under  3000  h.p.  since  in  this 
maximum  case  a  30,000-gallon  tank  would  provide,  in  the  event 
of  pump  failure,  cooling  water  for  one  and  one-half  hours.     Plants 
of   300    h.p.    or    less    will    find    a    wooden    tank    on    a    wood 
tower     quite     satisfactory,     Fig.      167.     A     12X12    ft.    tank 
of   2-inch    cypress    staves    will    hold    close   to    12,000    gallons 
and  can  be  erected  on  a  30-foot  tower  at  a  cost  of  $1200.     A 
tower  made  of  8X8  in.  yellow  pine  with  the  joints  reinforced 
by  steel  plates  and  braced  by  diagonal  steel  rods  is  amply  strong 
for  this  tank. 

Regulating  Floats. — Every  overhead  tank  should  be  fitted 
with  some  form  of  high-  and  low-water  alarm.     Such  a  device 


COOLING  SYSTEMS 


215 


appears  in  Fig.  168.  When,  due  to  faulty  circulation,  the  water 
level  in  the  tank  becomes  dangerously  low,  the  float  strikes  the 
lower  collar  on  the  shaft  A .  Its  weight  overcomes  the  resistance 
of  the  spring  E,  and  the  point  F  contacts  with  H,  causing  a  bell 


4*8"  Spaced       ««V/c*/%nb       tfl 
I?  rth  each  End  I/"   \ 


dx  8  'Cross  Pail  bolted 
to  Legs  a  net  12x12 
Base 


Concrete 
FIG.   167. — Wooden  tank  and  tower. 

to  ring  and  lighting  up  the  red  globes.  If  the  level  becomes 
high,  the  green  lamps  light  and  the  bell  rings.  In  either  event 
the  engineer  has  ample  warning  that  the  water  tank  demands 
attention.  This  is  a  positive  safeguard  against  damage  due  to  a 
pump  failure. 


216 


OIL  ENGINES 


A  somewhat  similar  system  can  be  arranged  to  operate  the 
starting  box  of  the  pump  motor  as  well  as  to  ring  an  alarm  bell. 

Cooling  Towers. — If  a  supply  of  cooling  water  can  be  secured 
from  a  shallow  well,  the  best  plan  is  to  install  a  power  well  pump 
and  allow  the  discharge  to  waste  into  the  sewer.  Unfortunately 
such  a  supply  is  seldom  available,  and  some  form  of  cooling 


-^-0000 
OREENLAMPS 


FIG.  168.— Regulating  float. 

tower  whereby  the  discharge  water  can  be  cooled  for  reuse 
becomes  a  necessity.  This,  in  most  installations,  consists  of  an 
upright  wooden  tower  filled  with  slats  down  which  the  water 
trickles  and  is  cooled  by  the  upward  current  of  air.  Like  all 
structures,  the  tower  may  be  constructed  at  an  expense  ranging 
from  a  few  hundred  to  several  thousand  dollars.  The  former 
cost  covers  a  simple  tower  for  a  small  plant,  while  a  large  installa- 
tion demands  the  more  expensive  construction. 

Plants   of  300  h.p.  will  find  the  tower  in    Fig.    169    fairly 


COOLING  SYSTEMS 


217 


economical  in  first  cost  and  amply  large  for  the  required  cool- 
ing. This  tower  can  be  erected  at  a  total  material  and 
labor  charge  of  $300.  The  sump  under  the  tower  is  made  24 


!*• —• 


>o 

SI 


I 

I 

W> 

a 

? 


inches  deep  but  can  easily  be  deepened  at  slight  expense.  The 
%X16  in.  foundation  bolts  should  be  inserted  at  the  time  the 
concrete  is  poured.  The  frame  of  4X6  in.  timbers,  resting  on 
6X6  in.  sills,  is  large  enough,  especially  since  the  ship-lap  sides 


218 


OIL  ENGINES 


further  strengthen  the  structure.  The  sides  are  sealed  with  the 
ship-lap  with  the  idea  of  having  the  air  currents  enter  the  tower 
under  the  bottom  row  of  baffles  and  pass  out  at  the  top.  If  the 
sides  are  open,  practically  no  circulation  is  set  up. 


"<"!  ^  ,'i 

= 

= 

-^ 

• 

sBH 

Mmin 

J 

f          I 

*  * 


The  discharge  from  the  engine  first  flows  into  the  main  trough 
and,  passing  through  a  series  of  holes  in  the  trough  sides,  enters 
the  distributing  troughs.  The  latter  are  notched  to  allow  the 
water  to  overflow  before  completely  filling  the  trough.  This 


COOLING  SYSTEMS 


219 


feature  is  of  advantage  when  the  troughs  settle.  The  holes  in 
the  main  trough  can  be  plugged,  thereby  offering  means  of  con- 
trolling the  distribution  of  the  water. 

Figure  170  shows  a  somewhat  similar  design  for  an  installa- 
tion of  1000  h.p.     In  the  particular  plant  where  this  tower  was 


used  a  cooling  pond  with  spray  nozzles  was  originally  employed. 
In  erecting  this  tower,  the  pond  was  retained  as  the  sump.  As 
the  drawing  shows,  the  tower  was  placed  on  the  pond  bank,  and 
a  drip  surface  E  of  1 X 10  in.  ship-lap  covered  with  three-ply  rub- 
beroid  roofing  was  placed  under  the  tower.  In  this  drawing 
the  tower  sides  are  boarded  tight  with  ship-lap.  However,  this 


220  OIL  ENGINES 

was  not  carried  down  below  the  bottom  baffles.  On  windy 
days  the  water  was  blown  out  the  open  sides  at  the  bottom,  caus- 
ing a  washing  of  the  bank  and  a  settling  of  the  tower  sills.  In 
erecting  a  tower,  the  sides  should  always  be  carried  well  down 
below  the  bottom  baffles. 

For  plants  having  a  capacity  of  1500  to  2000  h.p.  the  more 
elaborate  tower  design  in  Fig.  171  will  prove  more  suitable.  This 
tower  has  the  sides  covered  with  louvres  while  the  top  is  carried 
above  the  trough,  forming  a  chimney.  This  construction  pro- 
vides an  increased  volume  of  air  passing  through  the  sides  while 
the  chimney  gives  the  necessary  draft. 

Circulating  Pumps. — In  the  small  one-engine  plants  where  a 
single  operator  cares  for  the  machinery,  the  most  approved  type 
of  circulating  pump  is  either  an  outside  packed  triplex  pump  or 
a  horizontal  plunger  pump.  A  large  percentage  of  plants  have 
centrifugal  pumps,  but  this  type  is  dangerous  in  the  small  plant. 
If  an  overhead  tank  is  a  part  of  the  installation,  the  centrifugal 
pump  offers  no  objectionable  feature.  In  those  plants  not  possess- 
ing the  protection  of  the  overhead  tank,  the  loss  of  the  pump 
suction,  as  often  occurs  with  this  pump,  is  dangerous.  The  pump, 
in  small  plants,  should,  if  possible,  be  chain-driven  from  the 
engine  shaft  since  a  broken  belt  is  to  be  avoided  at  all  costs. 

Large  installations  usually  employ  motor-driven  centrifugal 
pumps.  With  the  overhead  storage  as  a  plant  protection,  this 
pump  is  by  far  the  best  for  large  plants. 

In  placing  the  pump,  the  suction  line  should  be  made  as  short 
as  possible  and  the  lift  kept  at  a  low  value.  In  discharging  into 
the  overhead  tank  the  pipe  should  run  to  the  top  of  the  tank 
rather  than  enter  the  tank  bottom.  This  places  a  constant  head 
on  the  pump,  and,  in  case  the  pump  suction  valve  leaks  the  entire 
tank  will  not  empty.  A  by-pass  line  from  the  tank  bottom  can 
be  run  into  the  pump  discharge  for  priming  purposes. 

Both  the  tank  and  the  cooling-tower  pumps  should  be  installed 
in  accessible  places  in  the  plant.  The  common  practice  of  put- 
ting the  pumps  in  out-of-the-way  corners  has  nothing  to  commend 
it.  The  various  water  lines  can  be  painted  in  different  colors; 
this  enables  the  operator  to  trace  out  a  line  with  a  minimum 
of  difficulty. 

Effects  of  Bad  Water. — In  many  Western  and  Southwestern 
states  bad  water  is  one  of  the  serious  problems  confronting  the 
Diesel  operator.  The  organic  matter  in  suspension  as  well  as 


COOLING  SYSTEMS  221 

• 

certain  mineral  salts  tend  to  deposit  in  the  cylinder  jacket  and 
cylinder  head.  These  deposits  must  be  removed  if  the  required 
cooling  effect  is  to  be  maintained.  Many  oil  engines  have  had 
the  cylinders  badly  distorted  as  a  result  of  heavy  scale  forma- 
tions. Deposits  are  especially  dangerous  when  formed  on  the 
heads  of  horizontal  engines.  The  expansion  and  contraction  of 
the  metal  causes  the  scale  to  flake  off,  exposing  a  red-hot  iron 
surface  to  the  cooling  water.  Local  fractures  result,  later  develop- 
ing into  cracks  across  the  cylinder  head. 

When  the  water  scales,  a  periodic  inspection  of  the  jackets 
is  necessary.  It  is  impossible  to  reach  all  the  scale  with  a  scraper; 
consequently  a  muriatic  acid  solution  should  be  left  in  the 
jacket  for  a  few  hours,  followed  up  by  a  thorough  flushing  with 
water.  If  the  deposits  are  heavy,  a  50-50  solution  of  acid  and 
water  may  be  used,  though  ordinarily  a  10  per  cent,  solution  is 
amply  strong. 

Practically  all  mineral  salts  will  not  settle  at  a  temperature 
lower  than  150°.  If  the  discharge  temperature  of  the  cooling 
water  is  maintained  below  this  point  but  little  scale  will  occur. 
This  low  temperature  affects  the  engine's  efficiency,  but  not  to 
any  marked  extent. 

Purification  of  Water  Supply. — If  a  plant  is  of  considerable 
size,  it  is  of  advantage  to  install  a  water  purification  plant.  The 
type  of  purification  system  to  be  used  depends  on  the  results 
desired. 

Sediment.  Mud.  Sand. — If  the  water  is  taken  from  a  stream 
holding  much  mud  or  sand  in  suspension,  a  large  settling  basin 
with  a  filter  on  the  cooling-water  suction  line  is  all  that  -is  nec- 
essary to  secure  a  satisfactory  cooling  medium. 

Bicarbonates  of  Lime  and  Magnesia. — The  removal  of  these 
salts  requires  a  purification  system  involving  the  employment  of 
chemical  reagents.  The  character  of  the  supply  water  must  be 
analyzed  and  the  correct  system  installed.  The  proper  course 
is  to  purchase  a  system  from  one  of  a  number  of  well-known 
manufacturers.  This  guarantees  a  certain  performance  of  the 
apparatus  installed.  A  fair  estimate  of  the  cost  of  a  purifier 
is  approximately  $7.50  per  horsepower  of  station  engine  capacity. 
The  majority  of  purifiers  are  based  on  the  lime  and  soda  process 
where  either  lime  or  soda  is  used  as  the  reagent,  at  times  in 
combination  with  other  chemicals. 


222 


OIL  ENGINES 


Exhaust  Distiller. — The  logical  method  of  water  purification 
is  the  employment  of  an  exhaust  distiller.  This  heater  is  placed 
in  the  engine  exhaust  line  and  absorbs  part  of  the  heat  contained 


Baffling 


Flange  Bolted 


nlilljll 


Heater  Supported 
on  Saddles. 


FIG.  172. — Make-up  water  distillery. 

in  the  exhaust  gases.  The  engine  cooling  water  ordinarily 
loses  3  per  cent,  of  its  volume  in  being  cooled.  The  make-up 
water  necessary  to  balance  this  loss  is  first  circulated  through  the 


Exhaust 


22^  Sewer     Cooling  Water   N  Raw  Water  Supply 
Discharge 

FIG.  173. — Schematic  layout  of  make-up  distiller  system. 

heater  and  is  converted  into  steam  at  atmospheric  pressure. 
This  steam  is  then  led  to  a  closed  heater  where  it  is  condensed 
by  cooling  water  from  the  source  of  supply.  The  heater  is,  in 
form,  nothing  but  a  steel  tank  filled  with  2-inch  tubes  through 


COOLING  SYSTEMS  223 

which  the  water  circulates.  The  heater  in  Fig.  172  has  both 
heads  flanged,  which  feature  allows  the  tubes  to  be  bored  out 
with  a  hydraulic  turbine  tube  cleaner. 

To  raise  the  temperature  of  the  feed  water  before  it  enters  the 
tank,  the  feed  line  can  easily  be  passed  through  the  engine 
exhaust  pot.  This  will  raise  the  temperature  to  about  150°. 
In  computing  the  size  of  heater  required  for  any  given 
plant,  1  sq.  foot  of  heater  surface  per  horsepower  will  be 
amply  large  to  absorb  all  available  exhaust  heat.  The  heat 
wasted  by  the  engine  will  average  3000  B.t.u.  per  horsepower, 
and  the  heater  will  abstract  2000  B.t.u.  This  will  give  roughly 
2  pounds  of  make-up  water  per  horsepower.  Since  the  cooling 
loss  will  not  exceed  3  per  cent.,  this  amount  of  make-up  water 
is  sufficient  even  when  the  quantity  of  water  used  exceeds  the 
usual  60  pounds  per  brake  horsepower.  Figure  173  is  a  schematic 
layout  of  a  make-up  water  system.  The  advantage  of  this 
method  of  water  supply  lies  in  the  absolute  purity  of  the  engine 
cooling  water. 

A  distiller  should  be  made  of  cast  iron  rather  than  steel  plate  to 
better  resist  the  corrosive  action  of  the  exhaust  gases.  No  foundry 
can  build  such  an  article  at  an  attractive  price  if  the  pattern 
cost  is  assessed  against  one  distiller.  To  date  no  manufacturer 
has  attempted  to  standardize  this  accessory.  A  very  serviceable 
one  can  be  obtained  by  adapting  the  S.  and  K.  Oil  Cooler  to 
distilling  purposes.  This  is  of  cast  iron  throughout  with  the 
exception  of  the  tubes  and  baffle  plates. 

Temperature  of  Cooling  Lines. — Each  engine  possesses  in- 
dividual characteristics  that  preclude  any  set  rules  as  to  the  tem- 
peratures that  should  exist  in  the  discharge  cooling  lines  from 
the  various  parts.  Table  II  is  the  schedule  that  is  followed  in 
a  plant  containing  three  500  h.p.  vertical  Diesels.  These  values 
give  the  best  possible  operating  results  as  applied  to  these 
particular  units. 

TABLE  II. — COOLING  WATER  DrscHARGE  TEMPERATURES 

Air-compressor  discharge 105°  F. 

Inter-  and  after-cooler  discharge 105°  F. 

Exhaust-header  discharge 130°  F. 

Cylinder-jacket  discharge 150-160°  F. 

Exhaust-valve  discharge 120°  F. 


CHAPTER  XIV 
LUBRICATION 

LUBRICATION  SYSTEMS.     LUBRICATION  SPECIFICATIONS. 
OPERATING  DIFFICULTIES 

General. — The  problem  of  lubrication  is  one  of  the  most  im- 
portant that  confronts  the  Diesel  engineer.  Many  individual 
engines  have  achieved  a  sorry  reputation  due  to  poor  lubrication 
facilities  or  to  mediocre  grades  of  lubricating  oils.  The  engineer 
does  well  to  insist  on  a  high  quality  of  oil,  and  he  should  see  that 
the  oiling  devices  function  properly.  If  the  lubrication  method 
is  incorrect,  a  proper  device  should  be  installed. 


FIG.   174. — Cylinder  lubrication  check  valve. 

Lubrication  Systems. — Two  lubricating  systems  are  at  present 
in  general  use.  The  most  popular  one  is  the  force-feed  design 
where  one  or  more  positive-driven  mechanical  oil  pumps  force 
the  lubricant  to  all  moving  parts  with  the  exception  of  the  crank 
bearings.  These  parts  are  generally  oiled  by  gravity  stream 
lubrication.  A  design  of  cylinder  oiling  that  is  coming  into  use 
employs  a  spray  check  valve  quite  similar  to  the  fuel  injection 
nozzle  of  a  low-pressure  engine.  This  valve,  Fig.  174,  passes 
through  the  cylinder  jacket  and  cylinder  wall.  The  mechanical 
oil  pump  is  timed  to  cause  the  lubricating  oil  to  be  injected 
through  this  nozzle  as  the  piston  is  below  the  central  point  of 
its  travel.  The  oil  sprays  on  to  the  piston,  covering  a  consider- 
able area  even  though  the  clearance  between  the  piston  and 
cylinder  walls  is  small.  The  piston,  as  it  moves  upward,  swabs 

224 


LUBRICATION 


225 


this  oil  over  the  cylinder  walls.  This  principle  of  cylinder 
lubrication  is  most  satisfactory  in  operation.  The  oil  is 
deposited  when  the  cylinder  temperature  is  fairly  low;  con- 


sequently a  decided  lubricating  effect  will  be  experienced  before 
the  flame  of  combustion  burns  the  lubricating  oil. 

Even  when  such  an  injection  device  is  not  employed,  the  oil 
is  always  forced  into  the  cylinder  by  a  mechanical  oil  pump. 
Although  several  makes  of  oil  pumps  are  in  use,  the  majority 

15 


226 


OIL  ENGINES 


of  domestic  Diesels  are  equipped  with  the  Richardson-Phenix 
Model  M  mechanical  oil  pump.  This  pump  is  shown  in  Fig. 
175,  where  the  course  of  the  oil  is  indicated  by  arrows.  ;. 

An  engineer  should  bear  in  mind  that  the  mechanical  oil 
pump  is  subjected  to  stoppage  of  one  or  more  oil  lines  due  to 
the  presence  of  bits  of  waste.  Consequently,  as  much  attention 
must  be  given  to  the  pump  as  to  other  parts  of  the  engine. 

Stream  Lubrication. — As  has  been  mentioned,  an  engine 
having  a  mechanical  oiler  for  the  cylinders,  as  a  rule,  employs 
either  drop  or  stream  lubrication  for  the  bearings.  The  stream 
system  is  preferable  since  a  sufficient  amount  of  oil  is  assured. 


FIG.   176.— R-P  filter  for  Diesel  engines. 


The  lubricating  oil  can  be  stored  in  an  overhead  tank  from  which 
piping  with  sight  feeds  leads  to  all  the  bearings.  The  oil,  after 
performing  its  mission,  flows  down  into  the  engine  crankcase. 
Collecting  in  the  case,  it  is  generally  led  out  into  a  receiver  tank 
or  into  a  filter.  Probably  the  best  plan  is  to  have  a  receiver 
tank  below  the  engine  into  which  the  oil  drips  can  discharge. 
After  the  tank  contains  a  half  barrel  or  so,  this  oil  can  be  pumped, 
either  by  motor  or  by  hand,  into  a  filter.  After  filtering,  it  can 
then  be  pumped  back  into  the  overhead  tank.  If-  a  good  filter 
is  purchased,  the  oil  can  be  reused  almost  indefinitely.  With 
a  filter  having  ample  filtering  area,  it  has  been  found  that  the 
renewal  of  oil  does  not  exceed  %o  °f  1  Per  cent,  of  the  oil  cir- 
culated. Figure  176  illustrates  a  well-known  filter  that  is  in 
general  use  in  Diesel  plants. 


LUBRICATION 


227 


Pressure-feed  Lubrication  System. — A  pressure-feed  system 
for  crankshaft  and  connecting-rod  bearings  is  employed  on  the 
Busch-Sulzer  Type  B  and  on  the  New  London  Ship  and  Engine 
Co.  Diesels.  This  system,  as  used  on  the  Busch-Sulzer,  is 
outlined  in  Fig.  17.7,  showing  the  drilled  crankshaft  and  connect- 
ing-rods, as  well  as  the  pump  and  filtering  mechanism.  The  oil 
is  forced  by  the  pump,  which  is  a  rotary  geared  to  the  air-com- 
pressor crank  disk,  into  the  lower  half  of  the  main  bearings  as 
indicated.  The  oil  flows  around  the  journal,  lubricating  the 


FIG.   177. — Busch-Sulzer  lubrication  system. 

entire  surface.  The  diagonal-drilled  passages  to  the  crank  pins 
once  each  revolution  register  with  the  oil  inlet  opening  in  the 
lower  bearing  shell.  This  allows  a  stream  of  oil  to  enter  the 
passage  and  to  flow  to  the  crank-pin  box.  The  connecting-rod 
also  is  drilled,  and  each  revolution  this  passage  aligns  with  the 
crank  end  of  the  diagonal  passage,  which  causes  a  supply  of  oil 
to  pass  up  the  rod  to  the  wrist-pin  bearing.  The  drip  from  the 
various  parts  is  caught  in  the  crankcase  and  from  there  flows 
through  the  filter  into' the  cooler.  The  pump  then  draws  the 
oil  from  the  cooler  to  be  reused.  In  order  to  seal  the  various 


228 


OIL  ENGINES 


parts  of  the  system,  the  oil  level  in  the  crankcase  should  be  around 
3  inches  before  the  engine  is  started  and  should  always  be  carried 
at  least  1  inch  in  depth  while  the  engine  is  running.  The  pump 
discharge  has  a  pressure  gage  attached ;  the  pressure  should  aver- 
age around  25  pounds.  The  gage  pressure  is  a  fair  indication 
of  the  condition  of  the  system.  If  the  pressure  shows  a  decided 
increase,  it  is  evident  that  part  of  the  discharge  lines  are  clogged 

with  dirt  or  waste.  If  the  pres- 
sure drops,  usually  one  or  more 
bearings  are  worn,  allowing  the  oil 
to  leak  out  the  ends. 

Since  the  pistons  are  water- 
cooled,  at  times  water  mixes  with 
the  oil  in  the  crankcase.  If  in 
any  considerable  amount,  there  [is 
danger  of  bearing  trouble.  A 
water  separator  along  the  lines  of 
Fig.  178  will  remove  any  entrained 
water.  It  should  be  connected 
between  the  crankcase  and  the  oil 
filter.  Being  provided  with  a 
drain,  any  water  caught  in  the 
separator  can  be  drained  off  each 
day.  A  sight  glass  at  the  side 
enables  the  operator  to  observe 
the  water  level.  It  is  evident 
that,  as  long  as  the  velocity  of 
the  oil  is  low,  any  water  entering 
the  separator  will  settle  at  the 
bottom  due  to  its  greater  weight. 
Splash  Oiling  Systems. — The 
splash  oiling  system  is  almost 

abandoned  in  Diesel  engine  practice.  It  was,  however,  the 
method  employed  on  the  first  American  Diesels  for  lubricating 
the  bearings  and  connecting-rod  brasses  as  well  as  the  piston. 
The  American  Diesel  Co.  used  a  mechanical  oil  pump  for  the 
purpose  of  lubricating  the  cylinder  walls  but,  in  fact,  depended 
on  the  splash  from  the  crankcase  to  meet  most  of  the  cylinder 
lubrication  demands. 

The  great  objection  to  the  splash  system  is  the  difficulty  of 
preventing  excessive  oil  deposits  forming  on  the  cylinder  walls; 


T 


FIG.    178. — Water  separator 
lubrication    system. 


for 


LUBRICATION  229 

the  oil  burns  and  gums  the  piston  rings.  Since  the  shaft  bear- 
ings are  covered  with  oil  emulsion,  it  is  impossible  to  detect 
loose  bearing  shells.  It  is  generally  conceded  that,  due  to  the 
air-tight  crankcase,  the  heat  passing  down  the  cylinders  vaporizes 
a  considerable  portion  of  the  oil.  Experience  proves  that  the 
lubrication  demands  are  high  with  the  splash  system.  On  many 
old  engines  the  splash  has  been  abandoned  in  favor  of  a  stream 
lubrication  system. 

Lubricant  Oil  Requirements. — The  qualities  which  a  lubri- 
cant must  possess  to  enable  it  to  be  used  successfully  in  the  cyl- 
inder of  a  Diesel  are  few  in  number.  First,  it  must  possess 
lubricating  qualities;  in  other  words,  it  must  be  able  to  form  a 
film  over  the  rubbing  surfaces  that  will  prevent  the  piston  and 
cylinder  from  touching.  Furthermore,  it  must  possess  a  low 
coefficient  of  friction.  The  oil  must  possess  sufficient  body  to 
enable  it  to  seal  the  clearances  between  piston  rings  and  grooves, 
thereby  preventing  loss  of  compression.  Finally,  the  lubricant 
must  have  a  fire  test  high  enough  so  that  it  will  not  be  burned  at 
the  temperature  in  the  cylinder  during  the  suction  and  exhaust 
strokes  and  during  the  final  part  of  the  power  stroke.  In  burn- 
ing, during  the  period  of  high  cylinder  temperatures,  the  oil 
should  leave  no  carbon  or  tarry  deposits.  Many  engineers  are 
of  the  opinion  that  the  lubricating  oil  should  not  be  burned.  In 
this  they  are  in  error  since  the  temperature  of  the  flame  produced 
by  the  combustion  of  the  fuel  oil  is  far  above  the  burning  point 
of  any  lubricating  oil.  If  too  great  an  amount  of  lubricant  is 
fed  into  the  cylinder,  only  the  top  surface  is  consumed;  the  part 
next  to  the  cylinder  wall  does  not  burn  but  merely  breaks  up 
into  its  several  constituents,  thus  leaving  a  residue  of  heavy 
carbon  on  the  walls.  The  best  oil  will  show  these  deposits  when 
fed  in  excessive  amounts. 

Much  of  the  trouble  of  carbon  deposits  on  the  cylinder  and 
piston  is  primarily  traceable  to  poor  filtering  facilities.  If  the 
oil  circulating  through  the  bearings  and  other  parts  is  filtered 
and  used  in  the  engine,  including  the  piston,  this  filtered  oil  will 
contain  fine  particles  of  carbon  held  in  suspension.  This  free 
carbon  settles  on  the  cylinder  walls  in  a  hard  flint-like  coat.  The 
remedy  is  the  purchase  of  a  filter  that  will  remove  all  but  the 
very  finest  of  these  particles.  Probably  the  most  advisable 
method  of  operation  is  to  use  only  new  oil  in  the  cylinder  lubri- 
cating oil  pumps  and  to  place  the  refiltered  oil  in  the  bearing 
oiling  system. 


230  OIL  ENGINES 

The  ordinary  plant  has  no  equipment  for  analyzing  the  oil 
purchased.  A  rough  method  of  ascertaining  if  the  lubricant  is 
free  from  a  gummy  residue  is  to  place  a  smear  of  the  oil  on  a 
clean  pane  of  glass.  After  the  glass  has  been  placed  in  the  sun 
for  some  time,  the  oil,  with  the  exception  of  the  gummy  remain- 
der, will  evaporate.  The  amount  remaining  indicates,  in  a  fair 
manner,  the  gumming  characteristics  of  the  oil. 

It  has  been  frequently  claimed  that  a  lubricant  from  an  asphal- 
tum  base  oil  is  more  desirable  in  the  Diesel  than  paraffine  base  oil. 
The  experience  of  many  operators  indicates  that  this  is  a  matter 
dependent  on  the  particular  engine  tested.  Frequently  an 
oil  is  purchased  with  the  understanding  that  it  has  a  paraffine 
base.  If  a  small  amount  is  placed  on  a  piece  of  paper,  the  paper 
will  become  translucent.  Upon  evaporating,  if  the  oil  is  of  a 
paraffine  base,  the  paper  returns  to  its  former  color;  if  the  oil 
has  an  asphaltum  base,  the  paper  will  have  a  darker  shade. 

The  most  important  detail  in  the  manufacture  of  lubricating 
oils  is  the  process  of  filtering.  All  Diesel  oils  should  be  filtered 
through  fuller's  earth.  However,  the  cheapest  oils  have  been 
treated  with  sulphuric  acid  in  place  of  the  fuller's  earth  process. 
The  acid-treated  oils  may  be  detected  by  suspending  a  polished 
brass  strip  in  the  oil.  If  left  for  several  days,  the  acid-treated 
oil  will  cause  the  surface  of  the  strip  to  become  somewhat 
mottled  in  appearance  due  to  the  formation  of  minute  pits. 

Lubrication  Oil  Specifications. — While  oils  of  widely  varying 
characteristics  give  excellent  service  in  many  plants,  the  following 
specifications,  if  adhered  to,  will  guarantee  the  procurement  of 
an  oil  that  will  give  satisfactory  results.  Practically  all  refineries 
have  a  lubricant  that  will  meet  these  requirements. 


LUBRICATING  OIL  SPECIFICATIONS 

Boiling  point 600-700°  F. 

Flash  point 325-500°  F. 

Fire  point 400-600°  F. 

Viscosity  at  100°  F.,  Sayboldt 550-800 

Specific  gravity,  Baume 18-24 

Carbon  content  per  cent 0.05-0.2 

Sulphur None 

If  the  lubricating  oil  is  to  be  used  on  the  compressor  cylinders, 
the  flash  point  must  be  above  450°. 


LUBRICATION  231 

Amount  of  Lubrication. — The  lubrication  consumption  varies 
over  wide  limits  in  various  makes  of  engines.  Table  III  gives 
values  that  follow  very  closely  the  amounts  necessary  on  engines 
from  200  to  600  h.p.  capacity. 

TABLE  III. — DIESEL  LUBRICATION  REQUIREMENTS 

Drops  per 
minute 

Air  compressor  cylinder 3-4 

Engine  cylinder 25-30 

Wrist  pin 10-15 

Crank  pin 15-25 

Helical  gears 5-10 

Governor .  .  . 4-8 

• ,       Exhaust  valve  stem 2-5 

Admission .  .  2-5 


CHAPTER  XV 
DIESEL  FUEL  OILS 

COMBUSTION.     CLASSIFICATION  OF  FUELS.     ACTION  OF  FUELS. 
FUEL  SPECIFICATIONS.     FILTERS.     TANKS 

Combustion. — The  process  of  combustion  which  takes  place 
in  the  cylinder  of  an  internal  combustion  engine  is  simply  a 
chemical  reaction.  In  actuality  the  cylinder  is  merely  a  chem- 
ist's retort  wherein  the  atoms  of  hydrogen  and  carbon,  which 
make  up  the  body  of  the  fuel  charge,  unite  with  the  oxygen  con- 
tained in  the  air  charge,  forming  oxides.  The  carbon  in  its 
union  with  oxygen  forms  either  carbon  monoxide  (CO)  or  carbon 
dioxide  (C02) .  In  this  latter  chemical  reaction  an  atom  of  carbon 
unites  with  two  atoms  of  oxygen  forming  one  molecule  of  carbon 
dioxide;  this  combustion  releases  14,600  B.t.u.  per  pound  of 
carbon  and  raises  the  remaining  unburnt  carbon  to  the  incan- 
descent point.  Unless  there  is  sufficient  oxygen  present  to  unite 
with  this  incandescent  carbon,  the  latter  unites  with  one  of  the 
oxygen  atoms  of  the  carbon  dioxide  (CO2),  causing  the  entire 
carbon  oxide  to  assume  the  form  of  carbon  monoxide  (CO). 
Since  the  reaction  is  incomplete,  the  heat  released  by  the  forma- 
tion of  carbon  monoxide  from  carbon  and  oxygen  is  less  than 
that  produced  by  the  complete  reaction,  CO2.  The  value  is 
approximately  4380  B.t.u.,  making  evident  the  heat  loss  when 
the  combustion  is  not  complete.  All  Diesel  cylinders  are  of 
ample  volume  to  give  sufficient  oxygen  for  complete  combustion. 
If  the  chemical  reaction  is  not  fully  carried  out,  it  is  due  to 
causes  other  than  an  insufficient  supply  of  oxygen.  In  most 
instances  the  defect  is  traceable  to  poor  atomization  wherein 
the  oil  charge  is  not  separated  into  particles  of  such  minute 
dimensions  that  each  carbon  atom  contacts  with  the  required 
oxygen  atoms.  If  the  oil  droplets  entering  the  cylinder  are  of 
fairly  large  diameter,  the  oxygen  is  in  direct  contact  with  only  the 
carbon  at  the  surface  of  the  droplet.  The  carbon  atoms  within 
the  droplet  must  receive  their  oxygen  from  the  carbon  dioxide 
formed  at  the  surface.  For  this  reason  the  engine's  efficiency 

232 


DIESEL  FUEL  OILS  233 

depends  on  the  degree  of  atomization  of  the  fuel  charge.  The 
chemical  reactions  taking  place  probably  follow  this  order: 

C  +    02  =    C02  (1) 

C  +  C02  =  2CO  (2) 

2CO  +     O2  =  2CO2  (3) 

The  hydrogen  atom  of  the  oil  molecule  also  unites  with  the 
oxygen,  forming  water  (H2O)  or  rather  water  vapor  commonly 
called  steam,  the  reaction  being  as  follows: 

2H2  +  O2  =  2H2O  (4) 

This  reaction  generates  62,100  B.t.u.  per  pound  of  hydrogen. 
The  equations  do  not  refer  to  the  actual  weight  of  the  carbon, 
oxygen  and  hydrogen  but  merely  indicate  the  relation  of  the 
atoms.  Since  the  atomic  weights  of  the  various  substances 
differ,  it  follows  that  the  weight  of  each  substance  entering  into 
the  reaction  depends  on  its  atomic  weight  wherein  a  hydrogen 
atom  has  unity  weight,  carbon  12  and  oxygen  16.  Furthermore, 
where  oxygen  and  hydrogen  are  not  in  combination  with  other 
gases,  both  oxygen  and  hydrogen  have  their  atoms,  or  most 
minute  particles,  in  groups  of  two  or  more.  Equation  (1)  can 
then  be  written 

C  +  O2  =  C02 
12  +  32  -  44 

indicating  that  12  parts  by  weight  of  carbon  combining  with 
32  parts  of  oxygen  form  44  parts  of  carbon  dioxide;  then,  1 
pound  of  carbon  requires  3%2  or  2.67  pounds  of  oxygen  to  be 
converted  into  3.67  pounds  of  CO2.  Since  a  pound  of  air  con- 
tains 2Koo  pound  of  oxygen,  there  are  11.6  pounds  of  air  re- 
quired in  the  combustion  of  1  pound  of  carbon.  Air  at  62° 
Fahrenheit  has  a  volume  of  13.14  cubic  feet  per  pound;  the  11.6 
pounds  then  have  a  volume  of  152.4  cubic  feet.  The  hydrogen 
reaction  (4)  can  be  written  as  follows : 

2H2  +  O2  =  2H2O 
4  +  32  =  36 

where  1  pound  of  hydrogen  requires  8  pounds  of  oxygen  or  34.78 
pounds  of  air. 

While  the  petroleum  oils  contain  hydrocarbons  of  a  varied 
structure,  the  equation  below,  covering  the  ethylene  series  of 


234  OIL  ENGINES 

hydrocarbons,  outlines  the  process  of  equating  the  reactions 
taking  place. 

C2H4  +  302  =  2CO2  +  2H2O 

28  +  96     =  88       +  36 

where  28  pounds  of  ethylene  require  96  pounds  of  oxygen  to 
form  88  pounds  of  carbon  dioxide  and  36  pounds  of  water  or 
steam.  Since  23  per  cent,  of  the  air  is  oxygen,  417  pounds  of 
air  are  required  to  consume  the  28  pounds  of  C2H4,  of  which 
77  per  cent.,  or  321  pounds,  is  nitrogen,  which  experiences  no 
chemical  reaction.  Then,  for  perfect  combustion,  the  percentage 
by  weight  of  the  exhaust  products  would  be 

C02  H20  N 

Carbon  dioxide  Water  Nitrogen 

20  8  72 

These  are  the  theoretical  percentages  and  are  quite  different 
from  those  obtained  on  an  actual  Diesel  engine  test  where  the 
percentages  obtained  were  as  follows: 

C02  CO  NO 

Carbon  dioxide  Carbon  monoxide  Nitrogen  Oxygen 

7.2  .2  81.6  11 

The  H2O  percentage  was  not  obtained  in  the  test.  This  analysis 
would  apparently  indicate  that  an  excessive  amount  of  air  was 
employed  due  to  large  cylinders  or  to  an  over-supply  of  injection 
air.  The  oxygen  percentage  could  be  reduced  by  shortening  the 
period  of  injection  valve  opening.  From  these  results,  which  were 
obtained  under  full-load  conditions,  the  conclusion  could  be  drawn 
that  the  engine  was  able  to  carry  a  considerable  overload. 

Fuel  Classification. — Liquid  fuels  that  are  available  for  use 
in  the  Diesel  engines  fall  into  three  groups.  The  first  includes 
those  hydrocarbons  of  the  paraffine,  olefiant  and  acetylene 
series,  such  as  are  familiarly  known  as  the  petroleum  oils,  the 
principal  family  being  the  paraffine  series  CnH2n4.2.  The  second 
group  covers  the  liquids  known  as  benzol  derivatives,  such  as 
coal  tars.  The  third  group  is  composed  of  the  many  vegetable 
oils  containing  hydrocarbons,  such  as  peanut  oil,  palm  oil, 
cocoanut  oil  and  oils  from  other  tropical  and  sub-tropical 
vegetation.  The  last  group,  up  to  the  present  time,  has  not 
been  used  commercially  since  their  cost  has  been  far  above  that 
of  the  petroleums.  The  coal  tars  are  employed  to  a  considerable 
degree  in  Europe;  Germany,  especially,  has  given  much  attention 
to  the  adaptation  of  the  Diesel  to  these  oils.  The  increasing 


DIESEL  FUEL  OILS 


235 


favor  of  the  tar  oils  has  been  largely  induced  by  the  low  cost  of 
these  oils  and  by  the  import  duty  laid  on  the  petroleum  oils; 
in  Germany  the  import  duty  is  equal  to  the  cost  of  the  fuel 
delivered  at  the  wharf. 

TABLE  IV. — FUEL-OIL  PRODUCTION  BY  DISTRICTS  IN  1916  AND  1917 


Field 

1916 
Barrels 

1917 
Barrels 

Appalachian 

23  009  455 

24  600  000 

Lima-Indiana  

3,905  003 

3  500  000 

Illinois 

17  714  235 

15  900  000 

Oklahoma-Kansas  

115,809,792 

147,000  000 

Central  and  Northern  Texas 

9,303  005 

1  1  000  000 

North  Louisiana  

11,821,642 

8,700  000 

Gulf  Coast  

21,768,096 

24  900  000 

Rocky  Mountain  

6,476,289 

9,200  000 

California  

90,951,936 

97  000  000 

Other  fields 

7  705 

300,767,158 

341,800,000 

In  the  United  States  no  fuel  other  than  the  petroleum  oils  has 
found  favor;  this  is  attributable  to  the  low  price  and  convenience 
of  these  oils.  Some  speculation  has  been  indulged  in  as  to  the 
advisability  of  using  the  American  tar  oils.  However,  this  will 
be  unnecessary  for  many  years  to  come.  Table  IV  gives  the 
production  of  crude  petroleum  for  the  years  1916  and  1917. 
Approximately  40  per  cent.,  or  150,000,000  barrels,  of  this  oil 
remains  after  the  gasolene,  kerosene  and  light  distillates  have 
been  distilled  off.  These  heavy  residual  oils  are  marketable  as 
road  surfacers,  boiler  fuel  and  Diesel  fuel  oils.  Since  the  Diesel 
plant  can  offer  a  higher  price  than  is  justified  by  the  boiler  plant, 
all  this  oil  may  be  regarded  as  a  potential  Diesel  supply.  The 
total  of  150,000,000  barrels  would  furnish  fuel  for  more  than 
10,000,000  h.p.  on  a  24-hour  service.  This  is  many  times  the 
total  Diesel  installation  in  America. 

Furthermore,  the  Mexican  oil  fields  are  of  vast  productive 
possibilities.  The  many  internal  disturbances  in  Mexico  have 
served  to  limit  the  output;  this  will  be  overcome  in  the  near 
future,  and  vast  quantities  of  Mexican  crudes  will  be  on  the 
market.  These  oils  offer  but  small  inducements  to  the  refiner 
since  they  carry  very  low  percentages  of  the  lighter  distillates. 
The  Mexican  oils  are  marketable  only  as  boiler  fuels  and  Diesel 


236  OIL  ENGINES 

oils.  Their  employment  in  a  Diesel  entails  more  attention  from 
the  engine  operator  than  do  the  higher  gravity  oils  of  the  United 
States.  There  is  no  constructional  grounds  for  ignoring  the 
Mexican  fuels  when  the  supply  of  the  American  oils  is  depleted. 

Of  the  petroleum  oils  of  the  United  States  those  of  the  Eastern 
and  Midcontinental  fields  prove  the  most  satisfactory  in  Diesel 
operation.  This  is  a  generality,  however,  and  oils  from  wells 
in  the  Southern  Texas  fields,  where  the  fuel  is  somewhat  similar 
to  Mexican  crudes,  give  excellent  results.  The  Diesel  plant 
can  purchase  oils  covered  by  rigid  specifications,  but  the  only 
positive  way  to  determine  the  suitability  of  an  oil  is  to  run  a  test. 
It  is  of  no  advantage  to  test  a  single  barrel  since  no  engine  will 
reveal  the  objectionable  features  of  a  fuel  on  a  one-barrel  test. 
The  lowest  quantity  to  experiment  with  is  at  least  ten  barrels. 

The  petroleum  oils  on  the  market  as  Diesel  fuels  range  from 
South  Texas  and  Mexican  crudes,  which  contain  too  small  a 
percentage  of  gasolene  to  justify  distillation,  up  to  40°  dis- 
tillate, which  is  actually  a  low-grade  kerosene.  Most  Diesels 
are  burning  fuel  oil  from  20  to  30°  Baume,  which  is  a  residue 
left  after  fhe  gasolene  and  kerosene  constituents  have  been 
distilled  out  of  the  crude  and  which  has  been  filtered  to  remove 
the  dirt.  This  oil  ordinarily  is  desulphurized,  which  process 
eliminates  practically  all  the  sulphuric  acid  which  was  introduced 
in  the  distillation.  This  fuel  oil  has  a  varied  color,  ranging  from 
light  yellow  to  a  deep  black.  The  color  is  no  criterion  of  the  gravity 
of  the  oil,  the  crudes  of  various  fields  differing  widely  in  color. 

The  Diesel  fuels  fall  under  the  following  grades:  Stove  Oil, 
Solar  Oil,  Gas  Oil,  Distillate,  Fuel  Oil,  Diesel  Oil,  Desulphurized 
Fuel  Oil,  Crude  Oil,  Tops. 

Stove  Oil.  —  This  a  trade  name  attached  to  a  low-grade 
kerosene  from  39  to  44°  Baume  gravity.  The  oil  is  ordinarily 
of  a  yellow-white  color  having  a  dirty  appearance.  It  is  quite 
serviceable  for  a  low-compression  engine  but  cannot  be  termed 
a  desirable  Diesel  oil  since  it  flows  very  readily  and  will  pass 
the  injection  atomizer  disks  without  being  broken  up.  Blowing 
into  the  cylinder  ahead  of  the  air,  it  produces  severe  preignitions. 
It  is  of  advantage  only  as  a  starting  oil  that  can  be  used  in  cold 
weather  for  the  purpose  of  warming  the  engine  before  the  heavier 
fuel  oil  is  introduced.  It  constitutes  a  serious  fire  hazard  if  any 
large  quantity  is  kept  on  hand.  Its  price,  which  averages  2  to 
4  cents  above  fuel  oil,  would  make  its  adoption  inadvisable  even 
if  it  were  an  otherwise  desirable  fuel. 


DIESEL  FUEL  OILS  237 

Solar  Oil. — This  is  a  trade  name  covering  some  of  the  lighter 
grade  distillates  and  may  vary  over  a  wide  range  in  gravity 
from  36  to  42°  Baume.  Like  stove  oil,  it  cannot  be  classed 
among  the  desirable  fuels  and  should  be  used  only  where  frequent 
starting  and  stopping  are  usual,  such  as  in  a  Diesel-engined  tug. 
Serious  preignitions  are  of  frequent  occurrence  with  this  fuel. 
Its  price  is  usually  some  2  cents  per  gallon  above  fuel-oil  quotations. 

Fuel  Oil. — This  term  covers  all  oil  residue  that  remains  after 
distillation  has  removed  the  gasolene,  kerosene  and  light  dis- 
tillates. Dependent  on  the  particular  crude,  the  fuel  oil  may 
vary  in  gravity  from  20  to  32°  Baume.  In  practically  all  cases  it 
is  black  in  color,  though  some  of  the  Eastern  oils  have  a  light 
color,  as  also  have  certain  North  Texas  fuel  oils.  When  properly 
filtered,  etc.,  it  is  the  most  desirable  fuel  that  can  be  purchased. 
Since  all  the  light  volatile  gases  have  been  removed,  there  is  no 
preignition  danger.  It  is  low  in  price  in  comparison  with  either 
crude  or  the  light  oils. 

Gas  Oil. — After  the  kerosene,  gasolene,  etc.,  have  been  re- 
moved, if  the  distillation  temperature  is  sufficiently  increased, 
all  the  remainder  of  the  crude  will  distil  over,  with  the  exception 
of  a  heavy  tarry  portion  which  is  sold  for  road  surfacing.  These 
heavy  distillations  are  called  gas  oils  and  are  sold  for  Diesel 
consumption.  They  are  superior  to  the  fuel  oils,  being  free  from 
asphaltum  residue,  but  their  price,  which  is  above  that  of  fuel 
oil,  somewhat  limits  their  application. 

Diesel  Oil. — This  is  a  refinery  trade  name  for  a  filtered  fuel 
oil.  It  is  sold  at  a  slight  advance  over  the  unfiltered  fuel  and 
has  a  ready  market  in  the  Midwest.  For  small  plants  where 
no  filtering  apparatus  is  installed  it  is  the  fuel  that  should  be 
purchased. 

Desulphurized  Oil. — The  oil  is,  as  its  name  indicates,  a  fuel 
oil  which  has  been  desulphurized.  As  customarily  sold,  the  fuel 
contains  a  considerable  percentage  of  distillates.  Its  use,  in 
preference  to  fuel  oil,  cannot  well  be  recommended  since  it  is 
sold  at  a  considerable  advance  in  price. 

Distillate  Oil. — -The  distillate  oils  range  in  gravity  from  30  to 
39°  Baume.  They  have  a  yellow-green  tinge  and  are  the  products 
of  a  distillation,  being  vaporized  at  a  higher  temperature  than 
is  kerosene  or  stove  oil.  They  are  ideal  fuels  for  hot-bulb 
engines,  but  the  price  is  entirely  too  high  to  be  attractive  for 
Diesel  use. 


238  OIL  ENGINES 

Tops. — Topped  oil  is  the  residue  after  the  gasolene  has  been 
removed.  It  is  not  commercially  offered  in  any  but  limited 
quantities  and  can  be  ignored  in  making  a  test  of  Diesel  fuels. 

Crude  Oil. — Within  this  class  fall  all  crude  oils  which  have 
undergone  no  process  of  distillation  and  which  are  marketed  as 
they  come  from  the  well.  With  the  exception  of  some  South 
Texas  and  Mexican  crudes  which  do  not  justify  distillation,  no 
crude  can  be  obtained  save  in  limited  quantities.  In  some  locali- 
ties the  owners  of  small  wells  sell  the  raw  crude  to  the  local 
plants.  Since  the  range  in  the  character  of  oils  forming  the  crude 
is  great,  it  is  not  a  desirable  oil.  The  gasolene  content  becomes 
a  fire  hazard  that  cannot  be  ignored.  The  functioning  of  the 
engine  on  the  crude  is  by  no  means  perfect.  The  Mexican  crudes 
do  not  carry  such  a  range  in  hydrocarbons  and  perform  fairly  satis- 
factorily if  the  engine's  fuel  nozzle  and  combustion  chamber  are 
designed  to  atomize  and  mix  the  air  and  fuel  in  an  efficient  man- 
ner. It  is  essential  that  the  heavy  crudes  be  heated;  a  tempera- 
ture of  150°  can  exist  in  the  fuel  line  without  a  fire  hazard, 
being  present.  The  pump,  however,  must  have  its  suction  under 
a  pressure  head  to  avoid  the  creation  of  oil  vapors  during  the 
pump  suction  stroke. 

Specifications. — The  following  specifications  are  quite  broad 
and  cover  all  oils  that  can  be  successfully  burned  in  the  Diesel 
engine.  A  few  plants  may  be  using  oils  of  a  heavier  character, 
but  investigation  ordinarily  will  prove  that  the  operation  is  not 
entirely  satisfactory. 

FUEL  OIL  SPECIFICATIONS 

Heat  Value. — Not  less  than  18,500  B.t.u.  per  pound.  Contractor  must 
give  low  heating  value  of  the  fuel  supplied. 

Gravity  at  60°  F. — With  engines  having  closed  fuel  nozzles  the  oil  shall 
not  be  heavier  than  20°  Baume".  For  engines  having  open  nozzles  the  oil 
should  not  be  heavier  than  16°  Baume.  The  oil  should  not  be  lighter  than 
36°  Baume". 

Residue. — Not  more  than  10  per  cent.  The  residue  is  that  portion  of 
the  fuel  remaining  in  the  cup  after  being  subjected  to  a  temperature  of 
300°  C.  (572°  F.)  for  120  hours. 

Flash  Point.— From  125°  to  250°  F.— dependent  on  the  engine. 

Burning  Point.— From  160°  to  300°  F. 

Sulphur. — Not  over  2.0  per  cent. 

Water. — Not  over  .3  per  cent. 

Ash. — Not  over  .05  per  cent. 


DIESEL  FUEL  OILS 


239 


Heat  Value  of  Fuel  Oils. — It  is  self-evident  that  the  oils  having 
a  higher  heat  value  are  more  valuable  than  those  oils  with  a  low 
heating  value.  All  other  qualities  being  equal,  the  comparative 
values  of  two  oils  are  in  direct  proportion  with  the  ratio  of  their 
heating  values.  If  oil  of  36°  Baume  gravity  having  18,000  B.t.u. 
per  pound  is  quoted  at  $3.60  per  100  gallons  or  $5.12  per  1000 
pounds,  an  oil  containing  20,000  B.t.u.  is  equally  attractive  at 
$4.00  per  100  gallons  or  $5.69  per  1000  pounds.  The  policy  of 
purchasing  oil  by  the  gallon  is  not  to  be  recommended,  although 
it  is  the  custom  to  quote  in  this  manner.  Orders  for  oil  should  be 
placed  on  the  pound  basis  since  the  heating  value  of  oil  is  so  com- 
puted. Since  the  pounds  per  gallon  of  fuel  oil  of  30°  and  20° 
Baume*  are  respectively  7.294  pounds  and  7.777  pounds,  it  is 
apparent  why  the  heavier  oil  is  worth  more  per  gallon. 

Gravity. — The  usual  method  of  indicating  the  weight  of  crude 
or  fuel  oil  is  by  the  Baume  scale.  The  numbers  of  this  scale  are 
given  by  the  formula : 

f  140  ^ 

Degrees  Baume  =  \          \  —  130 
I   s.g.  J 

where  s.g.  is  the  specific  gravity,  water  being  —  1  — .  The 
specific  gravity  can  be  determined  by  a  hydrometer.  The 
gravity  of  a  fuel,  in  itself,  is  of  no  vital  importance;  however,  it 
can  be  generally  employed  as  an  indication  of  the  oil's  freedom 
from  a  large  residue  content  and  from  a  heavy  percentage  of  the 
TABLE  V. — THE  BAUME  SCALE 


Degrees 
Baume" 

Pounds  per 
U.  S.  gallon 

Specific 
gravity 

Degrees 
Baum6 

Pounds  per 
U.  S.  gallon 

Specific 
gravity 

10 

8.336 

1.000 

26 

7.477 

0.897 

11 

8.277 

0.993 

27 

7.435 

0.892 

12 

8.219 

0.986 

28 

7.385 

0.886 

13 

8.161 

0.979 

29 

7.344 

0.881 

14 

8.102 

0.972 

30 

7.294 

0.875 

15 

8.052 

0.966 

31 

7.252 

0.870 

16 

7.994 

0.959 

32 

7.202 

0.864 

17 

7.935 

0.952 

33 

7.160 

0.859 

18 

7.885 

.0.946 

34 

7.119 

0.854 

19 

7.835 

0.940 

35 

7.069 

0.848 

20 

7.777 

0.933 

36 

7.027 

0.843 

21 

7.727 

0.927 

37 

6.985 

0.838 

22 

7.677 

0.921 

38 

6  .  944     4 

}      0.833 

23 

7.627 

0.915 

39 

6.902 

0.828 

24 

7.577 

0.909 

40 

6.869 

0.824 

25 

7.527 

0.903 

240 


OIL  ENGINES 


more  complex  hydrocarbons  that  are  difficult  to  burn  in  a  Diesel 
engine.  Table  V  is  a  table  of  the  relation  of  Baume  gravity  to 
pounds  per  gallon. 


Section  A-B 


TERRY  CLOTH 
Off  TURKISH  TOWELING 


A    — 


)    0    O 


BRASS 
-SCREEN 


FELT  GASKET' 


I     I    I 


I 


a  i  i  i 


,  1 1  nun 


FIG.  179.— Fuel  oil  filter. 

Residue. — The  residue  that  remains  after  an  oil  has  been  sub- 
jected to  a  temperature  of  572°  Fahrenheit  (300°  Centigrade) 
consists  of  coke  and  dirt.  The  most  serviceable  oil  is  that  oil 
which  has  the  minimum  percentage  of  residue.  The  coke  will 
not  burn  at  any  temperature  occurring  in  the  cylinder.  Pos- 


DIESEL  FUEL  OILS  241 

sessing  some  of  the  characteristics  of  tar,  it  settles  on  the  fuel 
and  exhaust  valve  seats,  resulting  in  leaks,  and  fouls  the  piston 
rings,  freezing  them  in  the  grooves  and  thereby  destroying 
the  engine  compression.  Frequently  the  coke  deposits  on  the 
cylinder  walls,  especially  if  there  be  any  rough  spots  on  the 
walls,  with  a  scored  piston  as  an  immediate  result. 

The  dirt  also  has  a  deleterious  effect  on  the  valves  and  piston. 
There  is  no  excuse  for  any  oil  being  dirty  as  filtering  will  remove 
all  the  dirt  in  suspension.  While  the  upper  limit  of  the  dirt  and 
coke  is  set  at  10  per  cent.,  a  value  of  half  this  amount  can  well  be 
adopted  as  the  upper  limit  of  the  residue  carried  by  the  oil.  For 
the  purpose  of  removing  any  dirt,  a  filter  such  as  is  illustrated 
in  Fig.  179  is  quite  satisfactory.  This  consists  of  a  flanged  tank 
carrying  a  brass  cylindrical  screen  which  is  provided  with  a  felt 
gasket  at  the  base;  the  upper  flange  holds  the  screen  against  this 
gasket.  Terry  cloth  is  wrapped  around  this  screen  as  indicated. 
The  filter  is  fitted  with  a  by-pass  not  shown.  The  large  area 
of  the  terry  cloth  enables  the  filtering  to  be  carried  on  at  a  slow 
rate.  A  1000  h.p.  filter,  12X24  in.  outside  diameter,  is  required 
to  filter  Jfo  gallon  per  hour  per  sq.  inch  of  screen  area;  this  gives 
a  velocity  of  .4  inch  per  minute.  The  terry  cloth  screen  may  be 
of  as  many  thicknesses  as  desired.  Three  folds  ordinarily  give 
ample  filtering  effect.  To  clean,  the  top  flange  is  removed,  the 
screen  lifted  out  and  new  cloth  wound  on  the  screen  while  the 
dirty  cloth  is  washed. 

Flash  Point. — The  flash  point  of  oil  is  merely  that  temperature 
at  which  the  oil  gives  off  a  vapor  that  will  ignite  in  the  presence 
of  an  open  flame.  This  point  should  not  be  below  125°  Cen- 
tigrade for  two  reasons.  First,  if  the  oil  has  a  lower  flash  point 
than  that  given  above,  there  is  a  fire  risk  due  to  oil  vapors  forming 
under  atmospheric  conditions.  Second,  if  the  flash  point  is  low, 
the  oil,  as  it  rests  in  the  engine  fuel  valve,  may  vaporize  and  ignite 
on  account  of  the  absorption  of  heat  from  the  injection  air  and 
the  cylinder  head.  If  the  flash  point  is  exceedingly  high,  the 
ability  of  the  oil  to  burn  in  the  short  time  allowed  during  the 
admission  period  is  lessened.  In  this  the  flash  point  is  merely 
an  indication  of  the  vaporizing  characteristics  of  the  oil. 

It  should  be  added,  at  this  point,  that  no  person  should  be  al- 
lowed to  approach  an  oil  storage  tank  with  an  open  light. 
Neither  should  an  unprotected  electric  lamp  be  dropped  into  the 
tank.  In  cleaning  out  an  empty  tank,  the  cover  should  be  re- 

16 


242  OIL  ENGINES 

moved  and  the  tank  left  open  for  at  least  forty-eight  hours  before 
a  man  is  allowed  to  enter  the  tank.  The  oil  vapors  dispel  very 
slowly;  more  than  one  death  is  traceable  to  carelessness  in  this 
matter. 

Burning  Point. — The  burning  point  of  an  oil  is  that  tem- 
perature at  which  the  oil  ignites  and  burns  in  an  open  cup.  By 
some  it  is  claimed  that  the  burning  point  in  no  way  indicates  an 
oil's  usefulness  as  a  Diesel  fuel. 

Nevertheless,  if  the  burning  point  is  high,  with  a  corresponding 
high  flash  point,  the  oil  will  cause  the  engine  exhaust  to  be  smoky. 
This  is  attributable  to  the  sluggish  rate  of  combustion.  If  the 
burning  point  is  fairly  low,  the  fuel  charge  need  not  be  so  thor- 
oughly atomized  to  obtain  perfect  combustion.  As  a  matter  of 
practical  operation,  a  fuel  oil  should  not  have  its  burning  point 
exceed  300°  Fahrenheit  or  150°  Centigrade. 

Sulphur. — The  sulphur  content  should  under  no  circumstance 
exceed  2  per  cent.  With  this  low  value  the  action  of  the  sulphur 
dioxide  on  the  cast-iron  parts  is  negligible.  Even  this  small  amount 
of  sulphur  will  attack  the  exhaust  pipe  line  if  a  water  line  runs  into 
the  exhaust  header  for  cooling  purposes.  In  the  presence  of  the 
water  a  formation  of  sulphuric  or  sulphurous  acid  occurs  with  a 
consequent  eating  of  the  header.  On  certain  early  Diesels  where 
water  was  introduced  into  the  exhaust  valve  pots,  the  corrosion 
from  the  sulphur  was  very  evident.  If  the  cooling  of  the  cylinder 
head  and  exhaust  header  is  carried  at  a  temperature  low  enough 
to  condense  the  H2O  resulting  from  the  process  of  combustion, 
sulphuric  acid  may  form  in  the  exhaust.  This  is  especially  true 
on  low  loads  when  the  operator  neglects  to  reduce  the  flow  of 
cooling  water. 

The  American  Diesels  had  splash  lubrication  employing  an 
emulsion  of  oil  and  water.  The  sulphur  dioxide  gas,  blowing 
past  the  piston,  came  in  contact  with  the  emulsion,  forming 
sulphuric  acid.  The  acid  attacked  all  the  iron  and  steel  parts  of 
the  crankcase  and  cylinder.  The  same  effect  may  be  observed 
in  engines  having  a  water-cooled  piston.  If  the  water  connec- 
tions leak,  small  portions  of  the  joints  will  show  the  effects  of 
acid.  A  corrosive  action  is  at  times  observed  in  the  cylinder 
immediately  below  the  head  joint.  This  is  undoubtedly  the 
result  of  water  seeping  past  the  flange  gasket  and  uniting  with 
the  sulphur  in  the  fuel. 


DIESEL  FUEL  OILS 


243 


Water. — The  presence  of  water  in  Diesel  fuel  oils  is  objection- 
able from  the  viewpoint  of  both  the  purchasing  agent  and  the 
plant  operator.  It  requires  no  argument  to  prove  that  it  is  of 
no  advantage  to  buy  the  water  content  of  the  oil.  The  water 
increases  the  net  cost  of  the  fuel  while  likewise  increasing  the 
freight  charges.  Ordinarily  this  is  not  of  great  moment  since 
the  percentage  of  water  is  never  large. 

The  engineer  is  justified  .in  protesting  against  an  excessive 
amount  of  water  since  it  increases  his  operating  difficulties.  In 
certain  fields  where  the  oil  comes  from  flowing  wells,  instead  of 
from  "pumpers,"  the  water  and  oil  exist  in  an  emulsion.  It  is 
practically  impossible  to  separate  the  water  and  oil.  The  emul- 


FIG.   180. — Tank  suction  line  float. 

sion  also  entrains  a  large  quantity  of  air  globules.  As  this  com- 
bination of  oil,  water  and  air  enters  the  fuel  pump  the  air  often 
breaks  away  from  the  oil  and,  collecting  in  the  pump,  disturbs 
the  functioning  of  the  valves.  The  air,  water  and  oil  mixture  has 
a  greater  volume  than  a  pure  oil  charge  of  equal  heating  value. 
This  increased  fuel  volume  demands  an  increased  air-injection 
pressure  to  force  it  into  the  cylinder. 

If  the  water  is  in  a  free  state,  it  will  settle  at  the  bottom  of  the 
oil  storage  tank.  If  this  is  not  drained  at  frequent  intervals,  the 
water  level  will  reach  the  end  of  the  fuel  suction  line,  with  the 
result  that  the  fuel  valve  injects  nothing  but  a  water  charge  into 
the  engine  cylinder.  The  engine  then  drops  its  load  and  slows 
down.  This  constitutes  one  of  the  most  serious  nuisances  that 
occur  in  a  plant.  When  it  does  happen,  the  entire  fuel  line  must 
be  purged  of  the  water  and  the  storage  tank  drained.  It  is 
practically  impossible  to  secure  oil  that  is  entirely  free  from  water. 


244  OIL  ENGINES 

The  storage  tank  can  be  arranged  with  a  float  which  will  permit 
the  oil  suction  line  to  be  below  the  fluid  level  at  all  times  and  yet 
never  touch  the  bottom  where  the  water  rests.  This  may  be  in 
the  form  of  a  barrel  float,  Fig.  180,  where  the  oil  line,  at  the  point 
where  it  enters  the  tank,  has  a  short  rubber  connection.  The  other 
end  is  plugged  and  is  fastened  to  a  keg  while  a  tee  and  nipple 
above  the  keg  allows  the  oil  to  enter  the  line.  The  keg  floats 
on  the  surface  and,  even  if  the  tank  is  almost  empty,  the  angle 
at  which  the  keg  rests  prevents  the  suction  nipple  from  touching 
the  bottom.  The  only  attention  required  is  the  occasional  re- 
newal of  the  rubber  hose. 

When  an  engine  ceases  functioning  in  all  the  cylinders,  it  is 
usually  an  indication  either  of  no  fuel  or  of  water-logging.  If 
there  is  no  fuel,  the  engine  ordinarily  first  runs  irregularly  before 
stopping.  With  water  entering  the  cylinder  the  cessation  of 
ignition  is  almost  instantaneous. 

Ash. — The  damage  resulting  from  the  presence  of  ash  in  the 
fuel  is  over-estimated.  This  residue  remaining  unburnt  in  the 
engine  cylinder  is  of  a  mineral  character,  being  silicate,  quartz  or 
iron  oxide.  There  is  no  doubt  that  any  decided  percentage  of 
these  substances  will  score  an  engine  cylinder.  Fortunately  no 
oil  is  offered  for  Diesel  fuel  that  has  an  ash  percentage  above  .05 
per  cent. ;  this  amount  is  so  slight  that  its  presence  is  not  revealed 
through  any  engine  trouble. 

Viscosity. — The  viscosity  of  an  oil  has  no  bearing  on  its  adapta- 
bility as  a  Diesel  fuel.  The  thickest,  most  sluggish  oil  can  be 
made  quite  free  flowing  through  the  application  of  heat.  In  the 
Northern  states  every  oil  storage  tank  should  have  heating  coils 
for  use  in  the  winter  months.  If  these  coils  are  connected  with 
the  discharge  cooling  water  before  it  enters  the  cooling  tower, 
the  heat  abstracted  is  ample  to  make  the  oil  free  flowing.  In 
the  cold  climates  it  is  always  advisable  to  have  a  tank  inside  the 
building  of  at  least  one  barrel  capacity.  If  shut-downs  are  of 
more  than  a  few  hours  duration,  the  engine  should  be  run  on 
kerosene  or  stove  oil  until  the  heavy  oil  becomes  fluid.  It  is 
necessary  to  drain  the  fuel  pump  and  lines  on  a  shut-down  to  pre- 
vent clogging  Of  the  lines  with  congealed  oil. 

Acid. — To  avoid  corrosion  in  the  pumping  and  cylinder  parts 
the  oil  should  be  devoid  of  any  trace  of  acid. 

Engine  Oil  Tanks. — Each  engine  should  be  supplied  with  an 
individual  oil  tank.  This  tank  is  best  elevated  with  its  base 


DIESEL  FUEL  OILS 


245 


at  least  5  feet  above  the  engine  fuel  pump.  This  places  a 
pressure  head  on  the  pump  suction  that  does  much  to  eliminate 
air  leakage  into  the  pump.  The  tanks  are  often  of  two  com- 
partments, one  of  which  holds  kerosene  for  starting  purposes. 


No.  408  Ring  i     o 
No  10  Lid       f     Screwed  Manhead 
'     Location  may  vary 


4 

^—^^~i 

LjLJ 

1 

to           1 
I 

3   i 

T 

1  

; 

Double 
Riveting 

o      r 

1 

<=  8-0-X-16-0-6000 
•^  8-0-x-21j3 

Gals  > 

^-  8000  Gt 
-x-26'8—  10, 
8^)"x-32-'o" 

l\K  & 

000  Galo 

] 

-12.  000  Gals. 

w 


/No.  10  Screwed  Manhead 
,£    to  be  located  as  desired 


Double 
Riveting 

| 

^  —  i 

j( 

11 

i     |   \ 

(      1 

1 

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1 

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GaU                       s- 

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-G.L. 


Size 

Capacity 

Heads 

Shell 

Riveted  with 

Weight 

8'         X  16' 

6,000  Gals. 

K" 

Me" 

H     Rivets 

5,000  Ibs. 

8'         X  21'-3^" 

8,000  Gals. 

w 

Ke" 

H     Rivets 

6,100  Ibs. 

8'         X  26'-8" 

10,000  Gals. 

%:" 

^Ke  ' 

H     Rivets 

7,200  Ibs. 

8'         X  32' 

12,000  Gals. 

&!, 

a^6'/ 

%    Rivets 

8,400  Ibs. 

10'-6"  X  23'-6'7 

15,000  Gals. 

Me" 

%     Rivets 

9.000  Ibs. 

10'-6"  X  31' 

20,000  Gals. 

y±" 

/l  6 

H     Rivets 

11,  000  Ibs. 

8'         X  16' 

6,000  Gals. 

H" 

K" 

Vv     Rivets 

6,100  Ibs. 

8'         X  21/-3H" 
8'         X  26'-8" 

8,000  Gals. 
10,000  Gals. 

Wf 

& 

K     Rivets 
%     Rivets 

7,600  Ibs. 
9,100  Ibs. 

8'         X  32' 
10'-6"  X  23'-6" 

12,000  Gals. 
15,000  Gals. 

£" 

% 

K     Rivets 
%     Rivets 

10,600  Ibs. 
11,000  Ibs. 

lO'-e"  X  31' 

20,000  Gals. 

H" 

H     Rivets 

14,000  Ibs. 

A  2"  Duplex  Oil  Tank  Vacuum  Valve  should  be  furnished  with  each  tank. 
FIG.  181. — Steel  oil  storage  tank. 

The  employment  of  kerosene  for  starting  is  advisable  in  all 
plants.  It  reduces  the  liability  of  the  engine  refusing  to  fire 
and  eliminates  the  tarry  deposits  that  frequently  occur  when  the 
heavy  fuel  oil  is  injected  into  a  cold  engine.  The  kerosene 


246 


OIL  ENGINES 


should  be  fed  for  ten  or  fifteen  minutes  on  starting  and  for  four 
or  five  minutes  before  stopping.  At  the  latter  time,  the  kerosene 
cuts  the  carbon  deposits  and  prevents  freezing  of  the  piston  rings. 
The  tank,  in  every  instance,  ought  to  have  a  level  indicator 
fitted  to  it.  A  simple  indicator  can  be  made  out  of  a  galvanized 
float,  two  pulleys  and  a  light-weighted  pointer.  The  oil  can 
be  pumped  into  this  tank  from  the  storage  tank  by  either  a 
hand  or  motor-driven  pump.  For  a  plant  of  less  than  300  h.p. 
the  quantity  of  oil  handled  does  not  justify  the  expense  of  a 
motor-driven  pump;  a  hand  rotary  pump  proves  quite  suitable 
and  is  low  in  cost. 


FIG.  182. --Steel  tank  setting. 

Oil  Storage  Tanks. — The  capacity  of  the  plant  together  with 
its  location  largely  determines  the  type  of  oil  storage  tank.  If 
the  plant  consumes  less  than  12,000  gallons  per  year,  two  steel 
tanks  of  6000  gallons  each  are  probably  the  most  advisable  size  to 
install.  The  employment  of  two  tanks  provides  means  whereby 
a  damaged  tank  can  be  repaired  without  a  plant  shut-down.  It 
allows  a  thorough  cleaning  of  the  tank  after  each  emptying. 
Figure  181  covers  the  steel  tanks  that  are  of  commercial  sizes. 

If  steel  tanks  are  installed,  they  should  be  set  in  a  pit  and 
covered  to  eliminate  any  fire  risk.  Figure  182  illustrates  a 
convenient  method  of  placing  the  tanks.  Concrete  saddles 
are  placed  in  the  pit;  the  tanks  rest  on  these  saddles.  The 
earth  is  filled  in  and  a  2-  to  4-inch  layer  of  concrete  is  formed 
around  the  tank,  completely  encasing  it.  This  concrete  layer 
prevents  any  corrosion  of  the  steel  plate  by  excluding  all  air 
and  moisture. 


DIESEL  FUEL  OILS 


247 


Where  the  ground  is  inclined  to  be  marshy  or  water-logged 
at  periods  of  wet  weather,  an  empty  steel  tank  has  sufficient 
buoyancy  to  float  on  this  water  and,  rising  up  above  the  ground 
will   break   the   pipe   connections.     To   avoid   this   danger,   in 
ground  of  this  character,  a  heavy  concrete  slab  can  be  run  about 


^.M:  •'•••'  '•"';• 


<D       i  ITD- 

Tank    Top 


FIG.   183. — Concrete  oil  storage  tank. 

the  upper  half  of  the  tank  or  concrete  beams  laid  across  the  top 
of  the  tanks  and  tied  to  the  saddles  with  long  rods.  The  weight 
of  the  concrete  then  overcomes  the  buoyancy  of  the  tank. 

Concrete  Storage  Tanks. — From  every  viewpoint  the  concrete 
storage  tank  is  the  most  advisable  to  install.     It  is  cheaper  than 


248  OIL  ENGINES 

a  steel  tank  of  a  corresponding  capacity  and  has  an  indefinite 
life  with  no  danger  of  leakage  if  the  concrete  is  well  reinforced. 

Figure  183  sketches  a  circular  concrete  tank  that  can  be  made 
of  any  desired  capacity.  The  bottom  must  be  well  reinforced  with 
steel  rods  or  hog  wire  fencing.  The  vertical  walls  should  have 
%-  to  %-inch  iron  rods  every  8  to  12  inches.  To  form  the  top, 
concrete  beams  can  be  placed  on  the  vertical  walls  and  covered 
with  concrete  slabs;  these  should  be  reinforced  with  wire  fencing. 

Coal  Tar  Oils. — Coal  tar,  as  a  Diesel  fuel,  has  received  no 
attention  in  the  United  States.  This  is  due  to  the  low  price  of 
the  petroleum  products.  While  it  will  be  years  before  the 
American  Diesel  operator  will  be  confronted  with  the  problem  of 
coal  tar  as  fuel,  this  fuel  has  its  future  possibilities.  There 
are  several  American  Diesel  engines  operating  on  Mexican  crude 
that  can  be  easily  adapted  to  tar  oils,  providing  a  fairly  constant 
load  is  carried.  Under  such  conditions  the  atomizer  will  nebulize 
the  tar  oil  sufficiently  for  ignition  without  the  employment  of  a 
primary  ignition  oil. 

Methods  of  Burning  Tar  Oils. — A  number  of  methods  have 
been  devised  to  successfully  burn  the  tar  oil.  The  following  list 
comprises  those  that  have  given  fairly  satisfactory  results. 

1.  Mixture  of  tar  oil  and  petroleum  oil. 

2.  Tar  oil  for  full  load  and  petroleum  for  light  loads. 

3.  Raising  thermal  range  of  the  engine  cycle. 

4.  Increasing  the  compression. 

5.  Application  of  a  light  oil  for  primary  ignition. 

6.  Catalytical  action. 

1.  Mixture  of  Tar  Oil  and  Petroleum  Oil. — Among  the  first 
plans  advocated  was  a  mixture  of  tar  oil  and  a  lighter  petroleum 
oil.  Various  experiments  have  been  made  with  a  varying  pro- 
portion of  coal  tar.  With  a  constant  load  the  coal  tar  percentage 
can  be  as  high  as  75  per  cent,  without  affecting  the  functioning  of 
the  engine.  The  problem  that  so  far  has  not  been  solved  is  the 
thorough  mixing  of  the  two  oils.  If  a  mechanical  agitator  is 
placed  in  the  engine  fuel  tank,  a  separation  of  the  oils  will  occur 
in  their  passage  to  the  fuel  valve.  The  consequence  is  an  irregu- 
larity in  the  ignition  of  the  charges.  This  method  can  hardly  be 
termed  successful  at  the  present  time. 

2.  Tar  Oil  for  Full  Load  and  Petroleum  Oil  for  Light  Loads. — 
There  is  no  condition  existing  within  the  engine  cylinder  that 
would  prevent  this  method  from  being  successful.  However, 


DIESEL  FUEL* OILS  249 

the  design  of  the  fuel  injection  system  presents  many  mechanical 
difficulties.  The  injection  valve  as  well  as  the  fuel  pump  must 
be  under  governor  control.  Figure  134  illustrates  an  injection 
nozzle  having  a  piston  valve  under  control  of  the  governor.  A 
tar-oil  line  and  an  ignition-oil  line  lead  to  this  piston  valve.  If 
the  load  is  light,  the  governor  shifts  the  valve,  causing  the  full 
charge  of  ignition  oil  to  enter  the  fuel  nozzle;  the  tar-oil  line 
is  placed  in  connection  with  the  tar-oil  return  line.  If  the 
engine  is  carrying  full  load,  the  movement  of  the  piston  valve 
uncovers  the  tar-oil  line,  allowing  the  tar  oil  to  enter  the  fuel 
nozzle  while  the  ignition  oil  flows  back  through  its  return  line. 
The  ignition-oil  line  to  the  nozzle  enters  the  nozzle  body  below 
the  tar-oil  entrance.  On  partial  loads  when  both  tar  oil  and 
ignition  oil  enter  the  fuel  nozzle,  the  ignition  oil  enters  below  the 
tar  oil,  thereby  being  blown  into  the  cylinder  and  igniting  before 
the  tar  oil  enters. 

3.  Raising  Thermal  Range  of  the  Engine  Cycle. — This  method 
includes  the  raising  of  the  temperature  of  the  injection  air,  the 
fuel  charge  and  the  cylinder  air  charge;  in  fact,  it  contemplates 
the  increase  of  the  temperature  of  the  entire  working  parts. 
Starting  with  a  higher  temperature  of  the  cylinder  charge  of  air, 
the  combustion  of  the  injected  fuel  takes  place  at  an  increased 
temperature.     This  insures  a  positive  ignition  of  the  tar  oil. 
The  thermal  efficiency  of  the  engine  depends  on  the  temperature 
range   t\  —  t2.     Although   the   actual   temperatures   ti   and   tz 
are  higher  than  usual,  the  range  ti  —  t%  is  identical  with  the 
normal  Diesel  temperature  range.     Consequently  the  efficiency 
would  not  be  changed.     The  objection  lies  in  the  increased 
stresses  occurring  in  the  engine,   and  the  method  has  never 
met  with  commercial  success. 

4.  Increasing   the  Compression. — The  plan  of  increasing  the 
compression  has  received  considerable  attention  but  is  not  com- 
mercially attractive.     The  Diesel  engine  under  present  designs 
works  with  as  great  a  pressure  as  is  advisable.     The  increase 
of  compression  pressure  would  augment  the  operating  difficulties 
and  is  dangerous.     Furthermore,  many  tests  of  engines  with 
varying  compressions  appear  to  bear  out  the  belief  of  practical 
engineers  that  a  compression  of  500  to  550  Ibs.  per  sq.  inch 
gives  the  engine  the  greatest  possible  efficiency  and  is  as  high  as 
is  practical.     The  injection-air  pressure  would  necessarily  be 
increased  a  corresponding  amount,  thus  increasing  the  engine 


250  OIL  ENGINES 

losses.     In  these  tests  referred  to,  the  engine  smoked  badly  at 
loads  below  half  rating. 

5.  Application  of  a  Light  Oil  for  Primary  Ignition. — This  plan 
is  the  only  one  offered  that  possesses  merit  and  has  been  employed 
to  a  large  extent  in  Germany  and  in  a  few  English  installations. 
The  fuel-injection  valve,  which,  in  most  cases,  is  of  the  open 
type,  is  equipped  with  two  oil  lines.     Figure  133  illustrates  the 
Korting  tar-oil  valve.     All  of  the  tar-oil  valves  are  designed  to 
allow  the  light  ignition  oil  to  be  blown  into  the  cylinder  ahead  of 
the  tar-oil  charge.     Being  lighter,  this  primary  charge  immediately 
ignites  and  supplies  the  additional  heat  required  to  ignite  the 
heavy  tar  oil.     The  time  interval  for  this  action  is  short  even  in 
a  slow-speed  engine.     Consequently,  it  cannot  be  expected  that 
an  engine  above  200  r.p.m.  will  successfully  handle  tar  oils  even 
under  this  system.     The  fuel  valve  becomes  foul  in  a  short  time. 
A  thorough  cleaning  is  necessary  at  least  once  a  week.     The  tar 
coats  the  piston  and  combustion-chamber  walls  with  a  thick  hard 
scale  that  requires  constant  attention. 

6.  Catalytical  Action. — No  commercial  engine  has  been  operated 
under  this  method  of  tar-oil  ignition.     A   catalytic   agent   is 
required  that  will  produce  combustion  even  when  the  tar  is  in 
fairly  large  particles.     The  cost  of  the  agent  and  its  life  are 
matters  of  importance.     It  is  highly  improbable  that  it  will 
ever  be  commercially  successful. 


CHAPTER  XVI 


FUEL  CONSUMPTION 

GUARANTEES.    TEST  RESULTS.     OPERATING  RESULTS.     GAS 

ENGINE,  DIESEL  AND  STEAM  TURBINE  EFFICIENCIES. 

DIESEL  INDICATOR  CARDS.     INDICATOR  RIGGINGS. 

METHOD  OF  CONDUCTING  DIESEL  TESTS 

Guarantees. — The  manufacturers  of  Diesel  engines  have  been 
very  conservative  in  the  guarantees  of  fuel  consumption  of  their 
engines.  Table  VI  gives  the  standard  guarantees  of  various 
builders,  although  all  are  lowered  in  tests.  All  of  these  guaran- 
tees, with  the  exception  of  the  Mclntosh  &  Seymour  and  the 
Busch-Sulzer  engines,  exceed  the  usual  European  Diesel  guaran- 
tees by  a  marked  amount.  However,  the  actual  fuel  consump- 
tion, by  test,  of  American  Diesels  is  not  much  greater  than  those 
of  the  European  engines.  The  difference  is  attributable  to  the 
superior  workmanship  of  the  latter  along  with  the  more  developed 
fuel-injection  devices. 

TABLE  VI. — MANUFACTURERS'  FUEL  GUARANTEES 


Make 

Type 

Size 

Full 
load, 
Ib. 

H 

H 

H 

National  Transit 

H  A. 

65-300 

0  48 

0.50 

0.58 

De  La  Vergne  
Korting 

H.  A. 
H.  A. 

100-300 
300 

0.42 
0.42 

0.435 
0.43 

0.52 
0.52 

Snow 

H  A 

65-600 

0  50 

0.52 

0.60 

McEwen  

H.  A. 

65-300 

0.48 

0.50 

0.58 

Nelseco 

V    M   A 

120-240 

0.50 

Fulton  

V.  M.  A. 

50-100 

0.50 

Busch  &  Sulzer  

V.  A. 

500 

0.425 

0.44 

0.52 

Mclntosh  &  Seymour.  . 
Mclntosh  &  Seymour  .  . 
Standard       Fuel      Oil 
Engine 

V.  A. 
V.  M.  A. 

H  B. 

500-1000 
600 

60-300 

0.42 
0.404 

0.50 

0.43 
0.50 

0.52 
0.56 

0.84 

H  =  horizontal  engines. 
V  =  vertical  engines. 
M  =  marine  engines. 
A  =  four-cycle. 
B  =  two-cycle. 


251 


252 


OIL  ENGINES 


Snow  Diesel  Fuel  Consumption. — Figure  184  is  the  result  of  a 
test  on  a  300  h.p.  Snow  Diesel.     It  will  be  noted  that  the  test 


0.60 
0.50 

S°-40 

CQ 

n  on 

11100  L'.t 

^9200  B.t 

Dfc 

B" 
£3 
_7400_B.t 

o 

Q. 

_5550_B.t 

H 
Gtj 

-3700-B-t 

J850_B.t 

u.            <^ 

U-  , 

^ 

. 

****<^vs  }$ 

11  1>. 

vs 

13.11.^-^ 

Pounds  Fuel 

0  O.| 

s  g  * 

^£2 

^ 

u 

Load 

FIG.  184. — Test  results  of  a  Snow  Diesel. 


0.60 


0.50 


0.40 


0.20 


0.10 


11400  B.tju. 
9500_B.t. 


.7600  -JB.t 


JBDOLBJLl 


J900_B.t 


40 


30 


20 


10 


Full 


50 


40 


30 


20 


10 


o  ^  H  \  Fun 

Load 
FIG.  185.— Test— Oct.  12,  1916—65  H.P.  McEwen  Diesel. 

gives  fuel  consumptions  that  are  20  per  cent,  lower  than  this 
company's  standard  guarantees. 

McEwen  Diesel  Fuel  Consumption. — Figure  185  shows  a  test 
on  a  65  h.p.  McEwen  Diesel.     The  fuel  consumption  at  full 


FUEL  CONSUMPTION 


253 


load  is  remarkably  low.  The  increase  at  three-quarters  and 
half-load  over  the  full-load  consumption  is  quite  marked.  From 
this  it  would  appear  that  the  engine's  rating  was  not  as  high  as 
it  should  be.  In  other  words,  the  rating  should  be  raised,  making 
the  engine  a  75  h.p.  unit. 


l.O 


Full 


Load 


FIG.  186. — Test  Standard  Fuel  Oil  two-stroke-cycle  Diesel. 


0.70 


Load 


Full 


FIG.  187. — Test  of  300  H.P.  Korting  Diesel. 


Standard  Fuel  Oil  Engine  Fuel  Consumption. — Figure  186  is 
the  result  of  a  test  on  a  120  h.p.  Standard  Fuel  Oil  two-stroke- 
cycle  Diesel.  This  test  is  fairly  representative  of  two-stroke- 
cycle  Diesel  engines  of  small  powers. 


254 


OIL  ENGINES 


Korting  Diesel  Fuel  Consumption. — Figure  187  shows  the  results 
of  a  test  on  a  300  h.p.  Korting  four-cylinder  horizontal  Diesel. 


0.7 

0.6 

0.5 

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14 


Load 


FIG.   188. — 100  H.P.  Korting  Diesel  using  tar  oil  and  an  ignition  oil. 
0.8 


10 


Load 


Full 


Fio.  189.— 500  H.P.  type  4B  Busch-Sulzer  Bros.  Diesel,  cylinders  16  X  24,  speed 

200  R.P.M. 

The  fuel  consumptions  and  thermal  efficiencies  are  extremely 
attractive. 

A  100  h.p.  Korting  Diesel  employing  tar  oil  as  a  fuel  was  tested 
with  the  results  appearing  in  Fig.  188.     A  light  distillate  was 


FUEL  CONSUMPTION 


255 


used  as  an  ignition  oil,  being  injected  ahead  of  the  main  tar-oil 
charge.  This  test  is  not  of  great  interest  to  the  operator  since 
the  results  are  plainly  inaccurate.  The  thermal  efficiency  at 
half  load  would  appear  to  approach  the  full-load  efficiency. 

Busch-Sulzer  Diesel  Fuel  Consumption. — Figure  189  shows  the 
results  of  a  test  on  a  500  h.p.  Busch-Sulzer  Type  B  Diesel.  This 
test  was  run  without  any  preparation  in  the  way  of  engine  adjust- 
ments and  represents  actual  operating  results. 

Mclntosh  &  Seymour  Diesel  Fuel  Consumption. — Figure 
190  is  the  result  of  a  test  on  a  500  h.p.  Mclntosh  &  Seymour 
Diesel.  This  engine  was  one  of  three  installed  in  a  Texas 

0.7  |i3050  B.t.u. ' ' ' ' |7° 


FIG.  190. 


10 
0  Vt,  V2  34  VM\\ 

Load 

500  H.P.  Mclntosh  &  Seymour  Diesel  engine,  164  R.P.M.,  Paris, 
Texas. 


electric  plant  and  was  direct  connected  to  a  437  kv.-a.  G.E. 
alternator.  In  running  this  test,  the  fuel  consumption  per  kilo- 
watt hour  was  obtained  at  the  various  loads.  Using  the  builder's 
guarantee  of  the  generator  efficiency,  the  fuel  per  brake  horse- 
power was  computed  from  the  fuel  per  kilowatt  hour.  The  units 
were  delivering  their  output  to  a  high-tension  line,  and  the  results 
represent  operating  conditions. 

Table  VII  outlines  complete  tests  on  three  500  h.p.  Mclntosh 
&  Seymour  Diesels  direct  connected  to  G.E.  alternators.  These 
tests  were  carried  out  while  the  engines  were  in  actual  service, 
delivering  current  into  a  100  kv.  high-tension  line.  The  efficiencies 
of  the  three  units  were  practically  uniform  and  represent  values 
that  are  about  as  high  as  can  be  expected  in  units  of  this  size. 


256 


OIL  ENGINES 


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Approximate  load. 

Kw.  (average)  

Load  factor  (kw. 
cent  
Kv.-a.  (average)  .  . 

1  i4 

Kw.-hr.  generated 
Time  start,  P.M.  ar 

Time  stop,  P.M.  ar 
Duration  of  test,  h 

Power  factor  (aver 
Kw.  for  excitation 
age)  

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Fuel  oil  consumed 

Fuel  oil  consumed  I 
Fuel  oil  per  kw.-hr 

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FUEL  CONSUMPTION 


257 


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Actual    Operating     Results. — The 

preceding  figures  represent  test  values 
at  certain  stated  loads.  It  is  im- 
possible to  secure  a  given  load  factor 
at  all  times.  Consequently  the  fuel 
consumption  of  a  Diesel  in  actual 
operation  will  not  check  with  test 
results.  In  a  few  instances,  such  as 
with  the  plant  containing  the  three 
500  h.p.  engines  appearing  in  Table 
VII,  the  plant  can  operate  at  prac- 
tically full  load  at  all  times.  The 
fuel  consumption  should  then  check 
with  test  results.  In  the  Paris, 
Texas,  plant  the  test  gave  a  fuel 
consumption  at  full  load  of  .603  Ib. 
per  kw.-hr.  The  actual  operating 
consumption  in  this  plant  is  .672  Ib. 
per  kw.-hr.  while  the  load  ranges 
from  three-quarters  to  full  load. 
This  is  but  10  per  cent,  above  the 
test  results. 

Unfortunately,  such  ideal  loads 
seldom  are  encountered.  The  usual 
Diesel  engine  carries  a  load  from  one- 
quarter  to  full  load,  and  the  fuel 
consumption  is  vastly  different  from 
full-load  test  results. 

Table  VIII  is  a  compilation  of  the 
hourly  loads  in  a  plant  containing 
three  old  225  h.p.  Diesels  and  a  500 
h.p.  Busch-Sulzer  Type  B  Diesel. 
The  500  h.p.  engine  has  an  individual 
fuel  tank  while  all  three  of  the  older 
engines  obtain  their  supply  from  a 
common  tank.  Hourly  readings  of 
the  fuel  consumed,  actual  kilowatts 
delivered  to  the  switchboard  and 
the  indicated  kilowatt  load  are 
entered  in  a  station  log.  It  will  be 
noted  that  the  500  h.p.  unit  operated 
sixteen  hours  daily  and  carried  a  load 


17 


258 


OIL  ENGINES 


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Units:  500  h.p. 
225  h.p. 

FUEL  CONSUMPTION 


259 


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260  OIL  ENGINES 

ranging  from  one-third  to  one-half  load.  One  hour's  fuel  con- 
sumption (from  9  A.M.  to  10  A.M.)  is  evidently  erroneous,  but 
this  was  rectified  in  the  subsequent  hourly  readings.  The  aver- 
age consumption  of  .71  Ib.  per  kw.-hr.  at  half  load  is  exception- 
ally good  and  is  evidence  of  the  high-class  attendance  employed 
in  the  plant.  The  interesting  figures  in  this  log  are  the  fuel  con- 
sumptions of  the  obsolete  225  h.p.  Diesels.  These  engines  are 
from  ten  to  fifteen  years  old  and  have  had  hard  service.  Never- 
theless, the  fuel  consumption  of  these  engines  at  less  than  half 
load  averages  .909  Ib.  per  kw.-hr.  Although  the  design  and 
workmanship  of  these  early  American  Diesels  are  often  ridi- 
culed, it  is  questionable  if  the  more  modern  engines  will  show 
any  better  results  after  the  same  length  of  service. 

Table  IX  is  the  summary  of  a  daily  log  of  a  plant  having  two 
225  h.p.  and  one  170  h.p.  old  Diesels  and  one  500  h.p.  Mclntosh 
&  Seymour  Diesel.  The  average  fuel  consumption  was  .972 
Ib.  per  kw.-hr.  This  high  value  is  due  to  the  condition  of  the 
old  engines  and  to  the  engineer's  unwillingness  to  have  the  500 
h.p.  engine  carry  the  night  load  even  though  it  was  less  than  the 
engine  rating.  Frequently  the  engineer  is  blameable  for  a  high 
fuel  consumption  since  he  is  unwilling  to  work  the  engines  at 
their  economical  load  factors. 

Production  Costs. — While  the  Diesel  is  superior  to  any  other 
form  of  prime  mover  in  thermal  efficiency,  the  actual  commercial 
efficiency  of  the  engine  may  be  even  less  than  a  steam  turbine 
at  low  loads.  It  is  obvious  that  the  Diesel  plant  investment  is 
high  with  consequent  high  interest  and  depreciation  (fixed) 
charges.  If  the  plant  is  operated  at  a  low  load  factor,  the  fixed 
charges  and  the  labor  charge  will  cause  the  total  cost  per  kw.-hr. 
to  be  excessive.  Figure  191  is  a  chart  which  shows  the  total  cost 
per  kw.-hr.  in  a  graphic  manner.  This  plant  had  a  total  installed 
capacity  of  500  kw.  The  entire  plant  cost  $81,600.  Table  X 
gives  the  various  charges  used  in  developing  the  curves  in  Fig. 
191.  It  is  apparent  that  the  two  factors  that  determine  the 
total  cost  per  kw.-hr.  are  the  labor  and  fixed  charges.  These  two 
items,  divided  into  hourly  charges,  are  assessed  against  the 
hourly  load  and  cause  the  total  cost  per  kw.-hr.  to  mount  very 
rapidly  on  low  loads.  The  solution  of  economical  Diesel  opera- 
tion is  a  high  load  factor  which  would  tend  to  reduce  the  overhead 
and  labor  charges.  This  particular  plant  employs  seven  men, 
and  the  capacity  could  be  doubled  without  any  increase  in  the 


FUEL  CONSUMPTION 


261 


labor  cost,  although  the  fixed  charge  would  increase  in  ratio 
with  the  engine  capacity.     These  curves  prove  that  Diesel  plants 


X  H 

Per  cent  Load 


Fun 


FIG.  l9l.  —  Influence  of  load  on  total  cost  per  kw.-hr. 

must  be  fairly  well  loaded  to  be  economical.  For  this  reason 
it  frequently  pays  a  plant  to  give  a  very  low  power  rate  in 
order  to  increase  the  load  factor. 


262 


OIL  ENGINES 


TABLE  X. — PRODUCTION  COSTS,  500  H.P.  DIESEL  PLANT  IN  MILLS 

PER    Kw.-HR. 


Load 

Interest 
and  de- 
preciation 

Fuel 

Labor 

Water 

Oil  and 
waste 

Main- 
tenance 

Total 

Full 

3.0 

4.2 

2.0 

0.1 

0.12 

0.12 

9.54 

H 

4.0 

4.2 

2.66 

0.1 

0.16 

0.16 

11.28 

H 

6.0 

5.0 

4.0 

0.1 

0.24 

0.24 

15.58 

H 

12.0 

6.3 

8.0 

0.1 

0.48 

0.48 

27.36 

Fuel  at  5  cents  per  gal. 
Labor: 

Chief  engineer  at  $150  per  month. 

Three  watch  engineers  at  $100  per  month. 

Three  helpers  at  $70  per  month. 
Overhead : 

7  per  cent,  interest 

8  per  cent,  depreciation 
15  per  cent,  total. 


TABLE  XI. — PRODUCTION  COST,  DIESEL  PLANT  AT  PLANT  C,  SEPT.  2,  1917 


Daily  plant  operation  report 
Co. 

To-day 

Month 
to  date 

Kw  -hr    output                            .        

1,930 

4,810 

Peak  load  kw  at  9  p  M 

150 

200 

Peak  load  factor  per  cent.         

57 

50 

Station  load  factor  per  cent 

11 

14 

Generator  load  factor  per  cent  

38 

29 

Fuel  used  (gals  oil)  Diesel  fuel  oil 

340 

762 

Fuel  used  per  kw.-hr.  output,  gals,  oil  

0.18 

0.16 

B  t  u  per  kw  -hr  output 

22,420 

Fuel  cost  —  total  (cents) 

884  0 

1,981.0 

Fuel  cost  (mills)  per  kw.-hr.  output  

4.6 

4.1 

Labor  cost  —  total  (cents) 

1,370  0 

2,740.0 

Labor  cost  (mills)  per  kw.-hr.  output  
Miscellaneous  cost  —  total  (cents)     .... 

7.2 
500.0 

5.7 
1,000.0 

Miscellaneous  cost  (mills)  per  kw.-hr.  output  .... 
Maintenance  cost  —  total  (cents)  

2.6 
700.0 

2.1 
1,400.0 

Maintenance  cost  (mills)  per  kw  -hr  output 

3.7 

3.0 

Production  cost  —  total  (cents)  

3,454.0 

7,121.0 

Production  cost  (mills)  per  kw.-hr.  output  
Time  generators  in  service  —  gen  hr 

18.0 
32 

15.0 
67 

Temperature  (deg.  F.)  circulating  water  
Siened  .  . 

76 

76 

FUEL  CONSUMPTION 


263 


Table  XI  is  the  daily  report  of  a  Diesel  plant  having  a  350 
kw.,  two  125  kw.  and  one  100  kw.  Diesel  units.  The  smaller 
units  are  very  old  and  have  a  high  fuel  consumption.  The  load 
factor  is  very  low  which  results  in  an  excessive  fuel  charge  even 
on  the  modern  500  h.p.  unit.  The  old  units  required  much  over- 
hauling,— this  shows  up  in  the  maintenance  charge.  The  total 
production  cost  was  18  mills  per  kw.-hr.  while  the  fixed  charges 
are  about  10  mills  per  kw.-hr.,  based  on  the  daily  output.  How- 
ever, this  total  cost  of  28  mills  per  kw.-hr.  compares  very  favor- 
ably with  steam  plants  having  similar  load  conditions. 

Table  XII  covers  the  results  of  three  months'  operation  of 
two  Diesel  plants  of  the  Texas  Light  and  Power  Co.  The  Paris 
plant  possesses  three  modern  500  h.p.  Diesels,  while  the  Tyler 
plant  has  two  double-engine  units.  These  latter  were  second- 
hand units  that  were  originally  installed  in  an  Eastern  industrial 
plant.  The  condition  of  these  units  is  revealed  in  the  main- 
tenance charge  of  4.48  mills  per  kw.-hr.  The  fuel  cost  of  the 
Tyler  plant  is  30  per  cent,  greater  than  in  the  Paris  plant. 


TABLE  XII. — ACTUAL  UNIT  PRODUCTION  COSTS,  PARIS  AND  TYLER  DIESEL 
STATIONS,  SEPT.  1  TO  DEC.  31,  1915 


Article 

Paris 

Tyler 

Data: 

Station  output  (m.  kw.-hr.)  

1  565 

499 

Rating  of  plant  (kw.)  .... 

1  050 

600 

Station  factor,  per  cent  

51 

28  K 

Total  fuel  oil  (gals.)  

149  072 

78  455  '; 

Pounds  oil  per  kw.-hr.  output 

0  672 

1  100 

B.t.u.  per  kw.-hr.  output  

13  100 

21,400 

Production  costs  (mills  per  kw.-hr.): 
All  labor  

1  44 

2  24 

Fuel  oil  

3  07 

5  18 

Water  .  . 

0  09 

0  19 

Lubricants  and  waste  

0  04 

0  56 

Miscellaneous  supplies  and  expense 

0  10 

0  29 

Maintenance  of  engines  
Maintenance  of  buildings  

0.04 
0  05 

4.48 
0  05 

All  other  maintenance  

0  15 

0  61 

Total  production  cost,  mills  

4.98 

13.60 

Oil  at  3  cents  per  gal. 


264  OIL  ENGINES 

This  cannot  be  attributed  entirely  to  the  mechanical  condition 
of  the  engines  but  to  the  load  factor  as  well.  The  fuel  consump- 
tion of  these  old  American  Diesels  is  less  than  10  per  cent,  over 
the  fuel  consumption  of  the  modern  Paris  engines  on  the  same 
load.  From  this  the  reader  can  rightly  conclude  that  the  effi- 
ciency of  the  Diesel  is  fairly  constant,  regardless  of  the  mechanical 
condition  of  the  units,  as  long  as  the  engine  will  function. 

Gas  Engine  Plant. — The  potential  competitor  of  the  Diesel 
engine  where  natural  gas  is  available  is  the  natural-gas  engine. 
Table  XIII  is  a  published  report  on  the  gas  engine  plant  of 
the  Willard  Storage  Battery  Co.;  this  report,  as  it  appears 
herein,  has  been  amended  by  the  elimination  of  the  depreciation 

TABLE   XIII. — OPERATING    DATA,    WILLARD    STORAGE    PLANT,    MONTH 

OF  JANUARY,  1912 

Rent  of  space  occupied $25 . 00 

Water  at  $0.40  per  1000  cu.  ft 20.77 

Gas  at  $0.30  per  1000  cu.  ft 511.80 

Repairs 70. 54 

Oil 101 . 88 

Labor..  396.00 


$1,125.99 
Credit— old  oil  barrels . .  9 . 05 


Net — with  no  credit  for  heating  from  cooling  water. . . .  $1,116.94 

Kw.-hr.  generated 122.428 

Cost  per  kw.-hr.  (mills) 9. 14 

B.t.u.perkw.-hr 13,935.00 

and  insurance  charges.  The  production  cost  totals  9.14  mills 
per  kw.-hr.  at  a  load  factor  of  41.8  per  cent.  This  is  in  striking 
contrast  with  the  Paris  Diesel  Plant  in  Table  XII  where  the 
production  cost  was  4.98  mills  per  kw.-hr.  and  is  only  slightly 
better  than  the  results  secured  with  the  Tyler  second-hand  units. 
The  heat  units  per  kw.-hr.  in  these  gas  engines  do  not  differ 
materially  from  the  B.t.u.  per  kw.-hr.  at  half  load  in  the  Diesels 
of  Table  XII.  The  advantage  the  Diesel  possesses  is  princi- 
pally in  the  lower  cost  per  B.t.u.  of  its  fuel  over  the  natural  gas. 
This  can  be  placed  in  the  form  of  an  equation. 

If  c  =  cost  of  fuel  oil  per  gallon  (19,000  B.t.u.  per  Ib.) 
a  =  cost  of  gas  per  1000  cu.  ft. 
y  =  B.t.u.  per  cu.  ft.  of  gas 


FUEL  CONSUMPTION  265 

then 


a 


V       133 

if  the  cost  per  B.t.u.  is  to  be  the  same  in  fuel  oil  and  gas.  As 
example,  if  fuel  oil  can  be  obtained  for  3  cents  per  gallon  and  the 
natural  gas  contains  600  B.t.u.  per  cubic  foot,  the  gas  must  be 
obtained  at  a  cost  of  13^  cents  per  1000  cubic  feet  to  equal  the 
fuel  oil  as  a  fuel. 

At  the  same  net  cost  per  B.t.u.  the  natural-gas  engine  would 
possess  a  lower  total  cost  per  kw.-hr.  because  of  its  lower  fixed 
charges.  Each  installation  must  necessarily  depend  on  the  vary- 
ing considerations  that  enter  into  the  problem. 

Producer-gas  Engines  vs.  Diesel  Engines.— From  the  view- 
point of  fuel  cost  alone,  the  producer-gas  engine  is  usually  more 
economical  than  is  the  Diesel.  Table  XIV  is  a  summary  of  a 
test  on  a  200  h.p.  producer-gas  engine  conducted  by  the  Lehigh 
University.  The  dry  coal  per  brake  horsepower  was  1.04  Ibs. 
Based  on  usual  generator  efficiency,  the  coal  per  kw.-hr.  would 
approximate  1J£  Ibs.  or  20,000  B.t.u.  The  coal  must  then  be 
purchased  at  $4  per  ton  to  allow  the  fuel  cost  to  equal  the  Diesel 
fuel  cost  in  Table  XII.  In  normal  times  anthracite  pea  coal 
can  be  purchased  at  a  decidedly  lower  price  in  the  vicinity  of 
the  mines. 

TABLE    XIV. — PRODUCER-GAS  ENGINE  TEST 

Duration  of  test .24  hr. 

Make  of  engine Fairbanks  Morse 

Type Four-stroke-cycle 

Size ' Four-cylinder  14>£  Xl8-in. 

Method  of  ignition Battery  during  test,  ordinarily  magneto 

Rated   capacity 200  h.p.   at   250   r.p.m. 

Kind  of  gas Mixed  producer  gas 

Average  Pressures  and  Temperatures 

Pressure  of  gas  near  meter,  in.  of  water 0. 985 

Temperature  of  cooling  water  Deg.  F. 

(a)  Inlet  to  cylinders  and  valves 53 . 74 

(6)  Outlet  from  cylinders 114.56 

(c)  Outlet  from  valves 104 . 95 

Temperature  of  gas  near  meter 62 . 3 

Temperature  of  exhaust  gases 1019. 23 

Gas  consumed  per  hour  at  62°  and  30  in 15,520  cu.  ft. 

Cooling  water  supplied  per  hour: 

(a)  To  jackets 9,000  Ib. 

(6)  To  valves 475  Ib. 


266  OIL  ENGINES 

TABLE  XIV. — PRODUCER-GAS  ENGINE  TEST. — (Continued.} 

Analysis  of  Exhaust  Gases  by  Volume 

Per  cent. 

Carbon  dioxide  (CO2) 16.99 

Oxygen  (O2) 1.84 

Carbon  monoxide  (CO) 0 . 50 

Nitrogen  (by  difference)  N2 80.67 

Indicator  Diagrams 

Pressure  in  Ibs.  per  sq.  in.  above  atmosphere: 

(a)  Maximum  pressure 300 

(6)  Pressure  at  end  of  expansion 25 

(c)   Exhaust  pressure  at  lowest  point 2 

Average  mean  effective  pressure  in  Ibs.  per  sq.  in 59 

Speed  and  Explosions 

Revolutions  per  minute 239 

Average  number  of  explosions  per  minute 478 . 5 

Indicated  horsepower 211 . 8 

Brake  horsepower 199 . 2 

Friction  horsepower  by  difference 12.6 

Percentage  lost  in  friction 5.8 

Economy  Results 

Heat  units  consumed  by  engine  per  hour : 

Per  indicated  horsepower 10,034  B.t.u. 

Per  brake  horsepower 10,674  B.t.u. 

Gas  consumed  per  hour: 

Per  indicated  horsepower 73 . 3  cu.  ft. 

Per  brake  horsepower 78  cu.  ft. 

Dry  coal  consumed  per  i.h.p.-hr 0. 98  Ib. 

Dry  coal  consumed  per  b.h.p.-hr 1 . 04  Ib. 

Efficiency 
Thermal  efficiency  ratio :  Per  cent. 

Based  on  i.h.p.-hr 25 . 3 

Based  on  brake  horsepower .  .  .  . ' 23 . 8 

Heat  Balance  Based  on  B.t.u.  per  i.h.p. 

B.t.u.  Per  cent. 

Heat  converted  into  work 2,545  25 . 4 

Heat  rejected  in  cooling  water. 2,700  26 . 9 

Heat  rejected  in  exhaust  gases 2,582  25.8 

Heat  lost  due  to  moisture  formed  by  the  burning  of 

hydrogen 228  2 . 2 

Heat  lost  by  incomplete  combustion 205  2 . 0 

Heat  unaccounted  for,  including  radiation 1,774  17. 7 

Total  heat  consumed  per  i.h.p.-hr 10,034        100. 0 


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FUEL  CONSUMPTION 


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268 


OIL  ENGINES 


E.,..  5000  S«U  •   II-15-J8 
8EJU>  WHITE  COPY'TO  DAIXAS  OTFICE 

J6BTAIN  ZELLOW  COPY  FOB  YOUR  OFFICE 

POWEK  STATION  AT. 


DAILY   POWER 


i 
Phase  VolUgeFwcia' 

OeB.1  K.W 

Amperes 

Cap. 
IND. 

Gen.  2  K.W.C 
Amperes 

*p. 

IND. 

Gen.  8  K.W.C 
Amperes 

^P.  
IND. 

Gen.  4         K.W,C 
Ampere's 

«p. 
IND. 

A 

B 

C 

Indiot 

A 

B 

c 

K.W. 

A 

B 

C 

K.W. 

A 

B 

C 

K.W. 

A 

B 

C 

K.W. 

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11 

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4 

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TOTAL  K.W.H. 


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2 

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K.W.H. 

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a.m. 

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Total 

INTERRUPTIONS 

STaEJJl-LIUHTB 

CIRCUIT 

OUT 

IN 

CAUBfi 

CIRCUIT 

ON  P-Jf  OM'A-MaJSlMoB'ttJSlMorf    K^il 

FIG.  192 


FUEL  CONSUMPTION 


269 


STATION   LOG 


ENDING  MIDNI.GHT. 


EXCITERS 


DIEbEL  FUEL~TAIiK 


IEMPERATURE 


D!.Ml|  Feed  'Atmoi 


4      •.«•*.•.••  J32 


10  11  12  1 


10  11  12        DEISEL  FUEL 


STEAM  FUEL 


Total  on  Hand  and  Beeoind 


_P«.e«Meter  K9,Jing 


Daj'.CoMumptlon 


Water  -  Present  Meter  Beadil^ 


Previous  Meter  Reading 


Dav's  Consumption 


Avg.  Vacuum  Engine  Ko.1 


OILS  AND  MABTE  U6ID  - 


Engine  Oil  Used 


Cylinder  Oil 


Cup  Grease 


Diesel  Crankcase  Oil 


Fuel  per  K.W.H. 


•WEATHER  CONDITIONS  !- 


General  Remarks 


K.W.H.-  Net  Station  Ontpnt 


K.W.H.  -  Delivered  to  Railway 


K.W.H.-  Delivered  to  SULightB 


270  OIL  ENGINES 

Comparative  Estimates  for  Diesel,  Steam  Turbine,  Natural- 
gas  and  Producer-gas  Engine  Plants. — Table  XV  covers  esti- 
mates on  various  types  of  prime  movers.  It  will  be  observed 
that  the  Diesel  engine  is  the  most  economical  unit  under  these 
conditions.  The  estimates  are  based  on  war  prices  and  should  be 
revised  to  prevailing  quotations  as  should  also  be  the  fuel  costs. 
The  producer  units  approach  the  Diesels  in  total  efficiency;  in 
fact,  in  most  cases  the  producer  unit  will  prove  more  efficient. 
The  serious  drawback  to  the  installation  of  a  producer  engine  is 
the  unreliability  of  the  producer.  This  apparatus  requires 
skilled  attendants  not  easily  procured;  producer  breakdowns 
are  of  common  occurrence  in  such  plants. 

Steam  vs.  Diesel. — In  large  units,  above  5000  kw.  the  steam 
turbine  will  probably  prove  more  economical  than  the  Diesel. 
Plants  of  less  capacity  will  find  that  the  Diesel  gives  a  lower  total 
cost  per  kw.-hr.  Under  1000  kw.,  the  turbine  is  not  as  attract- 
ive as  the  reciprocating  steam  engine  and  cannot  compete  with 
the  oil  engine.  If  a  manufacturing  establishment  or  office 
building  creates  a  demand  for  exhaust  steam,  the  Corliss  or  the 
Uniflow  steam  engine  may  be  the  type  to  install.  For  all  other 
plants,  where  no  demand  exists  for  exhaust  steam,  the  Diesel  is 
superior. 

Plant  Logs. — Every  power  plant  should  have  a  daily  log  in 
which  are  entered  the  hourly  load,  fuel  consumption  and  other 
details.  Figure  192  is  a  log  employed  in  a  number  of  Diesel  plants 
and  is  quite  complete.  Along  with  this  daily  log,  a  summary 
sheet,  such  as  appears  in  Table  XI,  should  be  maintained.  This 
sheet,  being  made  up  daily,  gives  the  management  a  check  on 
daily  efficiencies. 

Comparative  Heat  Balances. — Figures  193  to  195  show  graphic- 
ally the  heat  balances  of  various  prime  movers.  It  is  apparent 
from  these  comparative  charts  that  the  Diesel  engine  is  ap- 
proached in  heat-absorption  efficiency  only  by  the  natural-gas 
engine.  The  actual  efficiency  of  the  producer  engine  is  identical 
with  that  of  the  natural-gas  engine,  but  the  loss  occasioned  in 
the  producer  or  gas  generator  must  be  charged  against  the  engine. 

Indicator  Cards. — Many  Diesel  operators,  being  inexperienced 
in  handling  an  indicator,  do  not  understand  the  significance  of 
an  indicator  card.  For  these,  a  few  words  of  explanation  will 
not  be  amiss. 

It  is  obvious  that,  in  any  engine  cylinder,  we  are  confronted 


FUEL  CONSUMPTION 

Natural  Gas  Engine  Diesel 


271 


Exhaust  Gases 


Incomplete  Combustion 

14.4/0 
Radiation  and  other  Losses 

FIG.  193.  —  Heat  balances. 


Producer  Unit 


Diesel 


on  Loss 


Cooling  Water 


'•*! ,       ^ 

Exhaust  Gas  Loss    | 

20*  I 

Friction  Radiation 
and  other  Losses 

FIG.  194. — Heat  balances. 


Condensing  Steam  Engine 


Diesel 


28%    Exhaust  Gas  Loss 
2374  B.T.U. 


B.T.U. 


6%  Friction  Loss 
510  B.T.U. 

Cooling  Water  Loss 
2884  B.T.U. 


Radiation  and  Grate  Loss 
9%    2260  B.T.U. 

FIG.  195. — Heat  balances. 


272 


OIL  ENGINES 


with  the  problem  of  a  force  or  pressure  acting  on  the  piston  for  a 
certain  distance.  In  Fig.  196,  if  the  pressure  exerted  on  the 
piston  is  represented  by  the  height  of  the  mark  x  from  a  base 
line  yy'}  which  is  at  zero  gage,  or  atmospheric  pressure,  and  the 
distance  the  piston  moves,  while  pushed  by  the  pressure  x, 
indicated  by  the  distance  xx',  then  the  line  xy  multiplied  by  the 
line  xxr  will  represent  the  pressure  times  the  distance  moved; 
this  value  is  the  area  of  the  figure  xx'yy'.  The  area  of  this  card 


FIGS.  196,  197,  198. 

then  represents  to  some  scale  the  work  done  on  the  piston.  If 
the  height  xy  is  made.l  inch  and  represents  100  pounds,  and  the 
line  xx'  represents  1  foot  of  stroke,  then  the  area  obviously 
represents  100  pound-feet  or  100  foot-pounds  of  work  done. 
Since  a  horsepower  is  equal  to  33,000  foot-pounds,  this  engine 
would  have  to  make  330  of  these  strokes  per  minute  to  equal  one 
horsepower.  . 

With  an  actual  engine  the  line  xx'  is  not  horizontal  for  its  entire 
length.  In  Fig.  197  the  fuel  is  injected  and  burned  while  the 
piston  moves  from  x  to  a,  the  pressure  being  constant.  At  a 
the  fuel  valve  closes,  and  the  cylinder  is  rilled  with  a  charge  of 
hot  gases.  The  pressure  exerted  by  these  gases  on  the  piston 
forces  it  to  move  outward,  allowing  the  gas  pressure  to^drop. 
The  pressure  line  xx'  then  slopes  downward  toward  the  base  or 


FUEL  CONSUMPTION  273 

atmospheric  line  until  the  piston  reaches  the  end  of  its  stroke  at 
x1 '.  It  will  be  noted  that  the  gas  pressure  has  dropped  as  the  pis- 
ton receded.  The  area  of  the  figure  still  represents  the  work  per- 
formed on  the  piston.  Since  the  line  xx'  is  not  horizontal,  the 
area  is  no  longer  xx'  times  yyf  but  the  average  height  of  the  line 
xx'  times  the  actual  stroke,  which  is  yyf '.  This  area  can  be  deter- 
mined by  an  instrument  called  a  planimeter. 

In  an  actual  engine  at  the  end  of  the  stroke  the  exhaust 
valve  opens,  allowing  the  gas  to  blow  out,  and  the  line  xx'  drops 
sharply  from  xf  to  b,  Fig.  198.  The  piston  then  moves  forward, 
forcing  all  the  gas  out  of  the  cylinder.  This  gas  exerts  a  counter 
pressure  on  the  piston  which,  while  small,  is  indicated  by  the 
line  be.  As  the  piston  then  reverses  its  travel,  a  partial  vacuum 
is  formed  in  the  cylinder,  and  the  pressure  drops  below  the  atmos- 
pheric line;  this  causes  the  outside  air  to  rush  in.  Since  the 
pressure  is  below  atmospheric  in  the  cylinder  during  this  stroke, 
the  pressure  on  the  piston  has  a  negative  value  as  indicated  by 
the  line  cd  below  the  base  line.  At  d  the  suction  valve  closes, 
and  the  piston  compresses  the  charge  of  air.  The  pressure  rises 
as  the  piston  advances.  This  pressure  works  against  the  piston 
and  is  indicated  by  the  line  dx.  At  x  the  fuel  valve  opens,  and 
the  cycle  is  repeated.  The  area  of  the  figure  formed  by  these 
lines  represents  the  actual  work  performed  in  the  cylinder. 

The  cards  taken  from  various  Diesels  all  have  a  marked 
similarity.  A  few  typical  cards  are  shown. 

McEwen  Diesel  Indicator  Cards. — Figure  199  shows  cards  from 
a  14X22  McEwen  Diesel.  All  show  a  slight  drop  in  the  admis- 
sion line,  indicating  that  the  resistance  in  the  nozzle  was  too 
great  for  the  injection-air  pressure  carried.  Raising  the  air- 
blast  pressure  would  tend  to  bring  the  admission  line  to  a  hori- 
zontal position.  For  the  sake  of  clearness  the  exhaust  and 
suction  strokes  are  not  indicated. 

Allis -Chalmers  Indicator  Cards. — Figure  200  shows  typical  cards 
from  the  Allis-Chalmers  open-nozzle  Diesel.  The  rising  slope  of 
the  admission  or  combustion  line  indicates  that  the  fuel,  al- 
though injection  began  early,  did  not  ignite  readily;  at  the  be- 
ginning of  injection  only  the  lighter  portions  ignited.  This 
raised  the  temperature  sufficiently  to  ignite  the  entire  charge. 
The  effect  was  accumulative,  producing  the  rising  line. 

National  Transit  Indicator  Cards.— Figure  201  depicts  cards 
from  a  15J-£X24  National  Transit  Diesel  engine  at  180  r.p.m. 

18 


274 


OIL  ENGINES 


The  notable  feature  of  these  cards  is  the  horizontal  combustion 
line,  produced,  evidently,  by  a  happy  combination  of  efficient 
atomization  and  proper  air-blast  pressure.  The  quarter-load 
card  shows  a  sharp  peak  at  the  end  of  the  compression.  Some 
attribute  this  to  inertia  in  the  indicator.  It  is  very  probable 
that  this  peak  is  a  result  of  the  inability  of  the  air  blast  to  pick 
up  the  fuel  at  the  instant  of  valve  opening.  The  air  had  to 
attain  a  high  velocity  before  the  oil  was  swept  into  the  cylinder. 


ONE-FOURTH  LOAD 

FIG.  199. — Indicator  cards.     McEwen  Diesel. 


The  piston,  in  the  meantime,  had  retreated;  the  combustion 
of  the  fuel  was  insufficient  to  keep  the  pressure  constant. 

Standard  Fuel  Oil  Indicator  Cards. — Figure  202  shows  cards  for 
the  Standard  Fuel  Oil  two-stroke-cycle  Diesel  engine,  and  they 
are  typical  cards  from  an  engine  working  under  this  cycle. 

Faulty  Indicator  Cards. — Figure  203  is  a  card  from  a  two-stroke- 
cycle  Diesel.  The  compression  was  carried  to  the  end  of  the 
stroke  at  c.  On  the  power  stroke  the  combustion  did  not  occur 
until  the  pressure  had  dropped  to  the  point  a.  Since  the  oil 


FUEL  CONSUMPTION 


275 


No  Load 


Load 


10%  Overload 


FIG.  200. — Indicator  cards.     Allis-Chalmers  Diesel. 


FIG.  201. — Indicator  cards,   National  Transit  Diesel. 


276 


OIL  ENGINES 


was  light,  the  combustion  was  in  the  form  of  an  explosion,  the 
pressure  line  rising  to  b.  This  was  due  to  faulty  setting  of 
the  fuel  valve,  causing  it  to  open  late.  The  injection  pressure 


No  Load 


Half  Load 


Full  Load 


FIG.  202. — Standard  Fuel  Oil  two-cycle  Diesel. 

was  high,  and  this  forced  the  entire  fuel  charge  into  the  cylinder 
as  soon  as  the  valve  opened.     Figure  204  is  a  card  from  the  same 


be 


FIG.  203.— Two  cycle  engine  delayed 
ignition. 


FIG.  204. — Advanced  ignition. 


engine  with  an  advanced  timing  of  the  fuel  valve.     The  combus- 
tion was  initiated  when  the  compression  line  reached  the  point  c. 
Figure  205  was  taken  from  a  four-stroke-cycle  Diesel.     The 
compression  was  carried  to  a.     Due  to  the  heavy  character  of 


FUEL  CONSUMPTION 


277 


the  oil,  ignition  did  not  take  place  until  b,  where  the  entire 
charge  ignited,  raising  the  combustion  line  to  the  point  c.  Figure 
206  may  be  considered  a  perfect  card  and  is  from  the  same 


FIG.  206. — Perfect  combustion. 


FIG.  205. — Four   stroke   cycle   engine 
delayed  combustion. 

engine.  The  shape  of  the  combustion  ab  in  Fig.  207  discloses  a 
high  injection  velocity,  with  a  consequent  rapid  rate  of  combus- 
tion. With  a  lower  injection  pressure  the  combustion  would  be 


FIG.  207. — High  injection  velocity. 


FIG.  208. — Early  injection  using  a 
crude  oil. 


along  the  broken  line  ac.  The  peculiar  shape  of  Fig.  208  is 
traceable  to  early  timing  of  the  injection  valve  when  using  an 
untopped  crude  oil.  The  valve  opened  at  a;  the  gasolene  and 


FIG.  209. — Four  stroke  cycle  Diesel 
early  exhaust  opening. 


FIG.  210. — Late  exhaust  opening. 


kerosene  content  ignited,  raising  the  pressure  from  a  to  6.  The 
heavier  particles  did  not  ignite  until  the  piston  started  on  the 
return  stroke,  as  evidenced  by  the  point  c. 


FIG.  211. — Late  suction  valve  closure. 


Figure  209  shows  an  early  opening  of  the  exhaust  valve. 
Figure  210  betrays  a  late  exhaust  opening.     The  piston  reaches 


278 


OIL  ENGINES 


the  end  of  the  stroke  before  the  exhaust  valve  opens.  Figure 
211  reveals  a  late  closure  of  the  suction  valve;  this  valve  closed 
at  b,  producing  a  low  terminal  compression. 

Distorted  Cards. — The  process  of  combustion  occurring  in  the 
engine  cylinder  is  of  more  vital  interest  to  the  operator  than 
anything  else.  The  timing  of  the  valves  is  easily  checked 


Combustion  fc 


FIG.  212. — Distorted  indicator  card. 

while  the  actual  events  within  the  cylinder  must  be  deduced 
from  the  indicator  card.  With  the  usual  card  the  combustion 
line  is  of  small  length,  making  impossible  any  determination  of 
the  combustion  processes.  If  the  indicator  is  connected  in  such 
a  way  as  to  have  it  set  90  degrees  ahead  of  the  engine  crank,  the 


////////^^^^^ 

FIG.  213. — Indicator  rigging. 

combustion  line  is  exaggerated  in  length.  This  can  be  accom- 
plished with  the  indicator  rigging  in  Fig.  214  by  shifting  the 
eccentric  90  degrees.  A  card  secured  with  this  setting  appears 
in  Fig.  212.  It  is  apparent  that  the  lengthened  line  ab  gives 
an  increased  insight  into  the  cylinder  pressure  change  during 
combustion. 


FUEL  CONSUMPTION 


279 


Indicator  Rigging. — For  a  vertical  box-frame  engine  a  rigging 
along  the  lines  of  Fig.  213  can  be  easily  installed.  The  link  to 
the  piston  is  hinged  to  a  lug  which  is  cap-screwed  to  the  inside 
of  the  piston.  If  the  engine  stroke  is  24  inches,  the  leverage 
can  be  set  at  a  ratio  of  8  to  1,  giving  the  indicator  a  3-inch 
travel. 


FIG.  214. — Indicator  rigging. 

Figure  214  covers  a  form  of  indicator  rigging  that  can  be 
quickly  applied  to  any  type  of  oil  engine.  The  eccentric  c  is 
bored  to  fit  the  engine  shaft  D,  to  which  it  is  fastened  by  set- 
screws.  The  stand  B  is  of  cast  iron  and  supports  the  lever  A. 
This  lever  is  held  against  the  eccentric  by  the  spring  and  rotates 
the  indicator  drum  as  it  moves  up  and  down.  By  setting  the 
eccentric  so  that  its  throw  DDr  is  in  line  with  the  crank  throw, 
the  indicator  receives  a  true  motion  as  the  engine  revolves. 


CHAPTER  XVII 
THE  SEMI-DIESEL  OIL  ENGINE 

The  mechanism  of  the  Diesel  engine  is  rather  complicated, 
and  the  manufacturing  cost  is  too  high  for  the  small-powered 
units.  To  be  economical  in  total  expense,  a  Diesel  must  be 
at  least  of  100  h.p.  capacity.  Even  in  this  size  the  working 
hours  should  extend  over  the  major  portion  of  the  day.  The 
chief  objection  to  Diesels  below  150  h.p.  lies  in  the  high  attend- 
ance charge  per  horsepower-hour.  Regardless  of  the  size  of 
the  unit,  the  operator  must  not  only  be  intelligent  but  skilled 
as  well.  It  is  necessary  to  pay  fairly  high  wages  to  secure  the 
services  of  an  experienced  Diesel  engineer. 

To  meet  the  demand  for  an  engine  that  would  be  economical 
to  the  use  of  fuel  and  at  the  same  time  simple  enough  in  design 
in  permit  an  intelligent  workman  to  operate  it,  the  semi-Diesel 
engine  was  brought  out. 

As  has  been  explained  in  a  previous  chapter,  the  basic  principle 
of  the  present-day  Diesel  is  the  reception  of  the  heat  at  constant 
pressure.  While  the  term  "semi-Diesel"  has  been  applied  to 
certain  engines  because  their  compression  pressure  was  approxi- 
mately half  that  occurring  in  a  true  Diesel,  it  so  happens  that 
all  these  true  semi-Diesel  designs  embody  the  principle  of  re- 
ceiving a  part  of  the  heat  of  combustion  at  constant  pressure  and 
a  part  at  constant  volume.  A  great  many  low-pressure  engines 
are  marketed  under  the  trade  name  of  "  semi-Diesel. "  To  estab- 
lish the  right  of  an  engine  to  this  name  an  indicator  card  from 
the  engine  should  be  studied,  and  the  proper  classification  can 
be  determined  by  the  shape  of  the  combustion  line. 

Indicator  Cards  of  Semi-Diesel  and  Low-pressure  Engines. — 
An  indicator  card'  taken  from  a  two-stroke-cycle  low-compression 
engine  is  shown  in  Fig.  215.  The  compression  reaches  a  value 
of  approximately  100  Ibs.  per  sq.  inch  at  the  end  A  of  the  stroke. 
At  this  point  the  fuel  charge,  which  was  gasified  during  the  latter 
part  of  the  compression  stroke,  is  exploded  instantaneously.  The 
maximum  explosion  pressure  reaches  400  Ibs.  per  sq.  inch  at  B. 

280 


THE  SEMI-DIESEL  OIL  ENGINE 


281 


In  this  type  of  engine  all  the  heat  is  added  along  the  vertical 
line  AB,  at  constant  volume. 

Figure  216  is  a  card  from  a  four-stroke-cycle  semi-Diesel  engine. 
In  this  engine  a  charge  of  fresh  air  is  drawn  into  the  cylinder 
from  A  to  B  and  compressed  from  B  to  C.  At  the  point  C  the 
atomizer  explodes  a  primary  charge,  raising  the  pressure  to  about 
600  Ibs.  per  sq.  inch  at  D,  which  causes  the  injection  of  the 


FIG.  215. — Card  from  two-stroke  low 
compression  engine. 


FIG.    216. — Four-stroke-cycle  semi- 
Diesel  engine. 


secondary  or  main  fuel  charge  from  E  to  F.  This  main  charge 
is  injected  and  burned  at  practically  a  constant  pressure  of 
300  to  400  Ibs.  per  sq.  inch.  The  primary  charge  adds  but  a 
slight  amount  of  power  and  may  be  ignored  entirely  when  figuring 
the  indicated  horsepower.  If  the  sharp  peak  from  E  to  D  is 
eliminated,  the  card  will  have  a  form  which  to  all  appearances 
is  a  typical  Diesel  engine  card. 


FIG.  217. — Two-stroke-cycle  semi- 
Diesel  engine. 


FIG.    218. — De   La  Vergne    F.H.   semi- 
Diesel  engine,  200  spring. 


The  card  shown  in  Fig.  217  was  taken  from  a  two-stroke-cycle 
semi-Diesel  engine  and  displays  the  same  effects  of  the  primary  and 
secondary  charges.  Figure  218  is  a  card  from  a  De  La  Vergne 
Type  F.H.,  a  semi-Diesel  engine  using  a  vaporizer  and  air  in- 
jection but  without  a  primary  charge.  This  is  quite  similar 
to  the  true  Diesel  card,  the  chief  differences  being  in  the  maxi- 
mum compression  pressure  developed,  which  is  lower  than  in  the 
Diesel,  and  the  slight  increase  in  pressure  during  combustion. 

Comparing  these  semi-Diesel  cards  with  Fig.  215,  taken  from 
a  low-pressure  or  hot-bulb  engine,  it  is  evident  that  the  compres- 


282 


OIL  ENGINES 


sion  in  the  former  is  carried  much  higher  and  that  the  addition 
of  heat  is  accomplished  in  a  vastly  different  manner  from  that 
followed  in  the  low-compression  constant-volume  engine. 

Ignition  Devices.  Hvid  or  Brons  Principle. — Several  makes  of 
semi-Diesel  engines  use  the  "cup"  form  of  injection  and  atomiza- 
tion  of  the  fuel.  With  this  device  the  combustion  of  the  atomized 
fuel  is  accomplished  by  means  of  the  heat  of  compression, 
exactly  as  in  the  true  Diesel  engine.  The  sectional  view  in  Fig. 


Cross -Section 
of  CUD  A 

FIG.  219. — One  form  of  Hvid  ignition  device. 

219  shows  a  cup  employed  to  produce  the  injection  of  the  main 
fuel  charge.  The  operation  of  this  device  is  based  on  the  fact 
that  every  oil,  no  matter  how  heavy  it  may  be,  contains  some 
light  hydrocarbons  that  will  vaporize  or  distil  at  a  fairly  low 
temperature.  The  explosion  of  these  lighter  parts  of  the  fuel 
provides  the  propellant  whereby  the  remainder  of  the  fuel  is  in- 
jected in  a  finely  atomized  condition.  It  is  a  further  matter  of 
common  knowledge  that  the  temperature  of  ignition  of  an  oil 
is  dependent  upon  the  degree  of  atomization. 

In  Fig.  219  the  cup  or  primary  cylinder  A  has  ports  B  and  C 
that  communicate  with  the  outside  air  at  D  and  with  the  fuel 
supply  at  E.  As  the  piston  F  starts  on  its  suction  stroke,  the 
pressure  inside  the  cup  A  decreases,  as  the  joint  between  the  cup 


THE  SEMI-DIESEL  OIL  ENGINE  283 

and  the  cylinder  casting  is  not  tight.  The  reduced  pressure  in 
the  cup  causes  a  small  charge  of  air  and  oil  to  be  drawn  into  the 
cup.  The  oil  port  G  is  closed  by  the  action  of  the  governor,  there- 
by regulating  the  amount  of  the  fuel  charge.  At  the  proper 
point,  at  the  end  of  the  suction  stroke,  the  cup  moves  upward 
and  closes  the  fuel  and  air  ports  B  and  C,  and  at  the  same  time 
covers  the  communicating  port  H  in  the  side  of  the  cup.  As  the 
piston  returns  on  its  compression  stroke,  the  air  leaking  past 
the  joint  between  the  cup  and  the  cylinder  raises  the  pressure 
in  the  cup  to  from  350  to  400  Ibs.  per  sq.  inch.  The  resulting 
temperature  is  sufficient  to  vaporize  and  ignite  some  of  the 
light  hydrocarbons,  causing  a  maximum  ignition  pressure  inside 
the  cup  of  about  700  Ibs.  per  sq.  inch.  Just  before  the  crank 
reaches  dead-center,  the  cup  is  rotated  a  slight  amount,  uncover- 
ing the  port  H.  The  extremely  high  pressure  in  the  cup  immedi- 
ately forces  the  heavy  oil  charge  out  through  the  port  If 
into  the  cylinder  space.  In  passing  through  the  port  into  the 
low  pressure  existing  in  the  cylinder,  the  oil  is  atomized  suffi- 
ciently to  unite  with  the  air  charge  in  the  cylinder.  It  will  be 
observed  that  the  character  of  the  oil  determines  in  a  great 
measure  the  time  of  ignition  and  the  shape  of  the  combustion 
line  on  the  indicator  card.  If  the  oil  is  extremely  heavy,  with  the 
lightest  hydrocarbons  of  fairly  low  gravity,  then  the  light  portion 
will  not  ignite  in  the  cup  until  practically  dead-center  is  reached. 
The  pressure  in  the  cup,  due  to  this  primary  combustion,  will 
not  reach  a  high  value  before  the  port  H  is  opened.  The 
pressure  difference  existing  between  the  cup  and  the  cylinder 
will  not  be  great,  and  consequently  the  injection  through  the 
port  H  will  be  slower,  and  the  combustion  line  on  the  card  will  be 
practically  horizontal. 

In  the  card  shown  in  Fig.  242  the  oil  used  was  around  26° 
Baume  and  contained  a  considerable  percentage  of  light  oils. 
The  explosion  in  the  cup  was,  consequently,  intense,  causing  a 
high  pressure.  This  high  pressure  combined  with  the  explosion 
of  the  remainder  of  the  lighter  percentage  of  oil  as  it  entered  the 
cylinder  was  sufficient  to  cause  the  peak  on  the  card  at  dead- 
center.  The  heavy  particles  of  oil  burned  more  slowly,  as 
indicated  by  the  sloping  combustion  line. 

Operation. — In  operation  much  depends  on  the  adjustment  of 
the  cup-valve  stem.  If  the  movement  of  the  cup  uncovers  the 
port  H  too  early,  preignition  will  occur.  Since  the  pressure 


284  OIL  ENGINES 

carried  is  much  higher  than  in  the  low-compression  engine,  pre- 
ignition  has  a  greater  detrimental  effect.  Ordinarily,  the  bear- 
ings show  great  wear,  and  they,  as  well  as  the  shaft,  should  be 
made  heavier  than  is  customary. 

The  cup  has  a  tendency  to  become  fouled  with  carbon  and 
should  be  inspected  regularly.  Attention  should  be  paid  to  the 
beveled  seat  between  the  cup  and  the  engine  casting,  as  the  slight- 


FIG.  220. — Hvid  principle  of  ignition,  Lyons-Atlas  design. 

est  leakage  at  this  point  will  prevent  the  engine  from  operating 
satisfactorily.  The  seat  may  be  ground  with  coarse  emery  com- 
pound, finishing  with  a  mixture  of  pumice  flour  and  oil.  Cyl- 
inder oil  such  as  is  used  on  ammonia  compressors  makes  the 
best  paste. 

This  ignition  device  was  employed  on  the  St.  Mary's  oil  engine 
of  the  vertical  type. 

A  cup  device  on  the  same  lines  is  shown  in  Fig.  220.  This 
embodies  the  same  principle  of  primary  ignition,  but  the  cup  does 


THE  SEMI-DIESEL  OIL  ENGINE  285 

not  possess  the  angular  movement  for  the  purpose  of  opening  the 
port  H.  This  cup  is  equipped  with  a  fuel  valve  which  is  me- 
chanically operated  from  the  camshaft.  In  operation  a  charge 
is  drawn  into  this  cup  by  atmospheric  pressure  when  the  engine 
is  on  the  suction  stroke.  The  fuel  valve  controls  the  timing  of 
the  period  of  fuel  admission.  To  regulate  the  amount  of  fuel 
admitted,  the  needle  valve  E  is  connected  to  the  governor.  The 
movement  of  the  governor,  through  a  suitable  linkage  not  shown 
in  Fig.  220,  rotates  the  needle  valve  stem;  this,  in  turn,  alters 
the  area  of  the  fuel  port  or  passage  (7.  It  is  to  be  observed  that 
the  fuel  charge  enters  the  cup  on  the  suction  stroke  of  the  engine. 
It  remains  here  during  the  entire 
compression  stroke.  If  the  oil 
varies  in  character,  it  will  ignite 
earlier  or  later  as  the  case  may  be. 
There  is,  then,  a  danger  of  pre- 
ignition.  Figure  221  is  an  in- 
dicator card  taken  from  an  engine 
equipped  with  this  device.  The 
primary  explosion  occurred  when 


the  piston  was  approximately  20    Brons  principle. 
degrees  ahead  of  dead-center.     The 

injection  of  the  oil  from  the  cup  into  the  cylinder  and  the  igni- 
tion of  this  charge  took  place  some  15  degrees  after  dead- 
center  had  been  passed.  The  burning  of  this  main  charge  is 
shown  in  the  horizontal  line.  Apparently  the  combustion  of 
part  of  the  heavy  particles  was  somewhat  delayed,  the  burning 
taking  place  at  the  point  C. 

It  is  to  be  expected  that  this  cup  will  require  the  same  care  as 
the  one  previously  described.  Since  the  injection  is  not  posi- 
tively controlled,  the  openings  H  must  be  altered  in  size  to  regu- 
late the  flow  of  oil  through  them.  On  a  light  oil,  if  the  openings 
are  large,  the  injection  will  be  early,  causing  preignition.  The 
compression  carried,  averaging  450  pounds,  requires  a  sturdiness  of 
construction  approaching  the  Diesel.  The  cup  and  fuel  valve 
must  be  maintained  in  the  best  of  shape.  The  smallest  leak 
will  lower  the  cup  compression.  Since  the  explosive  pressure  ap- 
proximates 600  pounds,  it  is  evident  that  the  valve  must  be  ground 
often  and  with  the  utmost  intelligence.  As  there  is  no  water- 
cooling  of  this  valve  and  seat,  it  will  corrode  and  pit  if  it  does  not 
receive  attention.  This  device  is  found  on  the  horizontal  Atlas- 


286 


OIL  ENGINES 


FIG.  222. — Midwest-type  V.D.H.  horizontal  four-stroke-cycle  semi-Diesel  engine. 


FIG.  223. — Midwest  type  V.D.H.  vertical  semi-Diesel  oil  engine. 


THE  SEMI-DIESEL  OIL  ENGINE 


287 


Lyons  (now  Midwest)  V.D.H.  engines,  as  well  as  on  the  Burnoil 
engine.  An  illustration  of  the  V.D.H.  engine  appears  in  Fig. 
222.  The  governor,  which  is  of  the  spring-loaded  type,  is  driven 
off  the  lay  shaft  and  controls  the  fuel  needle  valve  E  in  Fig.  220. 

Lyons-Atlas  Vertical  V.D.H.  Engines. — On  their  vertical 
V.D.H.  engine  the  Lyons-Atlas  Co.  has  eliminated  the  governor- 
controlled  needle  valve  and  uses  a  fuel  pump  for  each  engine  cyl- 
inder, the  fuel  pump  being  under  governor  control. 

The  vertical  engine  is  illustrated  in  Fig.  223.  The  cylinders, 
which  are  9-inch  bore  by  13-inch  stroke,  are  mounted  on  A-frames. 
On  one  side  the  frames  are  open,  being  supported  by  tension  rods. 
The  openings  are  covered  by  steel  oil  guards  that  are  removable. 
The  cylinder  construction  is  quite  unusual.  Each  cylinder  is 
provided  with  a  removable  skirt.  This  skirt  can  be  unbolted, 
allowing  the  piston  to  be  swung  out  to  the  side  without  unship- 
ping the  connecting-rod  from  the  crank.  The  engine  is  built 
for  both  stationary  and  marine  service. 

Fuel  Consumption.  Hvid  Engines. — The  fuel  consumptions 
of  the  various  engines  employing  the  Hvid  principle  are  prac- 
tically the  same.  Table  XVI  covers  tests  on  a  three-cylinder 
vertical  engine,  9j-2-inch  bore  by  lOj^-inch  stroke,  and  is  quite 
representative  of  this  type. 


TABLE  XVI. — TEST  ON  SEMI-DIESEL  ENGINE  EMPLOYING  HVCD  PKINCIPLE 


Test  No. 

I 

II 

III 

IV 

Bore  of  cylinder,  in 

9>3 

9H 

9K 

9H 

Stroke,  in. 

10>£ 

10K 

10H 

io>£ 

Fuel  

Kerosene 

Standard  Oil 

Lansing  fuel 

Weight  per  gallon,  Ibs. 

6  9375 

fuel  oil 
7  1875 

Co.  fuel  oil 
7  375 

6.9375 

Weight  per  pint,  Ibs  
Gravity,  deg.  Baum6  
Flash  open  flame,  deg.  F  
R  p  m 

0.8672 
42 
160 
315 

0  .  8984 
33 
200 
330 

0.922 
29 
196 
345 

0  .  8672 
39 
210 
340 

Pounds  pull  net 

191 

191 

191 

191 

Brake-arm  circle  circum.,  ft  
Torque,  Ib.-ft  

33 
1003  3 

33 
1003  3 

33 
1003  3 

33 
1003.5 

Horsepower.  ...         

60  165 

63  03 

65  895 

64.94 

Fuel,  Ibs.  per  b.h.p.-hr.  .  .  .        ... 

0.586 

0  500 

0.481 

0.466 

Operation  of  engine  

Smooth 

Very  smooth 

Smooth 

Smooth 

Exhaust  

Clear 

Trace  of 

Almost 

Trace 

Engine  troubles 

None 

smoke 
None 

clear 
None 

None 

Maximum     b.h.p.     with     slight 
smoke  

60.16 

85.00 

84.15 

86.70 

288 


OIL  ENGINES 


Nordberg  Ignition  Device. — Another  form  of  ignition  cup, 
adopted  by  the  Nordberg  Manufacturing  Co.  for  their  two-stroke- 
cycle  semi-Diesel  (or  high-compression,  as  the  manufacturers 
call  it)  engine,  appears  in  Fig.  224.  The  fuel  oil  is  injected 
into  the  cup  A  through  the  atomizing  nozzle  B,  by  the  action  of 
the  fuel  pump,  a  few  degrees  before  mid-point  in  the  compression 
stroke.  This  fuel,  as  it  leaves  the  injection  nozzle,  mixes  with  the 
air  which  has  been  forced  into  the  cup  by  the  advancing  engine 
piston.  As  with  the  devices  already  discussed,  the  lighter  con- 


WATE R  INLET 
' 


FIG.  224. — Nordberg  semi-Diesel  igniter. 

stituents  ignite  as  soon  as  the  oil  enters  the  hot  cup  and  mingles 
with  the  air.  The  combustion  of  this  part  of  the  oil  charge 
creates,  within  the  cup,  an  extremely  high  pressure,  which  is 
much  greater  than  the  engine  compression  pressure.  This  dif- 
ference in  the  two  pressures  causes  the  remainder  of  the  fuel 
charge  to  be  forced  out  through  the  ports  marked  C.  The  high 
velocity  of  the  fuel  passing  through  the  ports  C  atomizes  it  suffi- 
ciently to  produce  ignition  when  mixed  with  the  air  charge  in 
the  cylinder. 

In  this  engine  the  point  of  injection  of  the  fuel  into  the  cup  is 
about  mid-stroke  of  the  piston.  Since  the  timing  of  the  injection 
of  the  main  charge  from  the  cup  into  the  cylinder  is  not  under 
positive  control,  with  certain  oils  preignition  may  occur.  If 
the  oil  is  of  light  gravity,  the  high  compression  pressure  carried 
will  cause  it  to  ignite  very  early.  This  primary  explosion  forces 
the  main  charge  into  the  cylinder  before  dead-center,  causing 


THE  SEMI-DIESEL  OIL  ENGINE 


289 


preignition  and  bearing  pounding.  To  avoid  premature  combus- 
tion, the  cup  is  designed  with  a  water-cooled  space;  this  assists 
in  keeping  down  the  temperature  of  the  cup  and  delays  combus- 
tion. 

Figure  225  is  a  later  design  of  cup.     In  this  the  water-cooling 
is  discarded.     The  injection  nozzle  is  provided  with  a  spring- 


FIG.  225. — Nordberg  ignition  device  on  semi-Diesel  engine,  late  design. 

loaded  check  valve  and  is  held  in  position  by  a  screwed  lock 
bushing  instead  of  a  locking  bar  as  was  used  on  the  former  design. 
The  bowl  of  the  cup  is  bolted  to  the  body  of  the  igniter;  this 
eliminates  the  difficulty  experienced  with  the  screwed  ring  collar 
of  the  previous  cup. 

Figure  226  shows  an  indicator  card  from  this  engine.  The  card 
reveals  combustion  conditions  that  are  not  along  the  true  Hvi  d 
plan.  It  would  appear  that  the  primary  charge  did  not  explode 

19 


290  OIL  ENGINES 

until  dead-center  and  that  the  piston  retreated  some  distance 
before  the  pressure  difference  caused  the  injection  of  the  main 
charge  and  its  consequent  combustion.  Under  such  injection 
conditions  a  dull  thump  would  be  heard,  produced  by  the  burning 
gases  striking  the  receding  piston.  If  the  injection  had  been 
early,  as  is  usual,  a  sharp  sound  would  have  been  emitted  as  the 
primary  charge  impinged  on  the  advancing  piston. 


Atmos. 


FIG.  226. — Power  and  scavenging  cards,  Nordberg  semi-Diesel  oil  engine. 
Cards  reproduced  to  scale.  Power  card  is  300  pounds  per  inch,  scavenging 
card  10  pounds  per  inch. 

Fuel  Pump. — The  Nordberg  semi-Diesel  engine  is  equipped 
with  a  fuel  pump  shown  in  Fig.  227.  The  pump  plunger  is  driven 
by  an  eccentric  keyed  to  the  engine  shaft,  while  the  fuel  charge  is 
regulated  by  the  closure  of  the  by-pass  valve  V  which  is  under 
governor  control.  The  fixed  eccentric  moves  the  pump  plunger 
P  on  the  outward  stroke,  drawing  in  a  charge  of  oil.  As  the 
plunger  reverses  and  moves  inward  on  the  discharge  stroke, 
the  oil,  displaced  by  the  plunger,  escapes  through  the  by-pass 
valve,  which  is  held  open  by  the  cam  F.  This  cam  is  rocked 
through  an  angle  by  the  governor  eccentric  rod  G.  At  the  proper 
time  the  cam  is  moved  to  its  mid-position,  as  shown  in  Fig.  228. 
The  by-pass  valve  closes,  and  the  oil  displaced  by  the  further 
movement  of  the  pump  plunger  passes  through  the  discharge 
valve  H  and  enters  the  fuel  atomizer. 

Governor. — Figure  228  outlines  the  relative  positions  of  the 
governor  and  pump  at  the  beginning  of  the  fuel-injection  period. 
The  governor  is  of  the  inertia  type  and  carries  a  pin  B  to  which 
is  fastened  the  by-pass  valve  rod  G.  The  governor  is  fulcrumed 
at  J  on  the  flywheel;  the  position  of  the  governor  pin  B  is  such 
that  the  by-pass  valve  is  just  closed  when  the  engine  crank  is  at 


THE  SEMI-DIESEL  OIL  ENGINE  201 

n 


292 


OIL  ENGINES 


A  on  full  load.     As  the  engine  revolves,  the  cam  moves  away  from 
the  by-pass  valve  stem  and,  returning,  opens  it  when  the  point 


Engine 


FIG.  228. — Diagrammatical  lay-out  of  governor  and  pump  action. 

B  has  moved  180  degrees.     Figure  228  shows  the  crank  position 
A  when  the  cam  has  just  closed  the  by-pass  valve.     I  is  the 


Load 


FIG.  229. — Nordberg  semi-Diesel  timing  diagram. 

position  of  the  pump  eccentric  at  this  time;  this  gives  a  total 
maximum  discharge  angle  of  30  degrees,  as  shown.  D  represents 
the  position  of  the  crank  at  no  load;  this  gives  a  discharge  angle 


THE  SEMI-DIESEL  OIL  ENGINE 


293 


of  5  degrees.     From  the  figure  it  is  evident  that  the  oil  is  injected 
before  mid-stroke  of  the  engine  piston. 

Valve  Timing. — The  timing  diagram  of  the  Nordberg  semi- 
Diesel  appears  in  Fig.  229.  Since  this  engine  is  two-cycle,  the 
piston  acts  as  the  exhaust  and  air-admission  valves;  the  exhaust 
and  admission  periods  are  dependent  on  the  location  of  the 
ports  in  the  cylinder  and  are  fixed. 


•  -V-  v-  — .-  —  TTTmt^ 


FIG.  230. — Nordberg  semi-Diesel  two-stroke-cycle  oil  engine. 

Nordberg  Engine  Frame. — Figure  230  illustrates  the  engine 
section  and  plan.  The  frame  is  of  heavy  construction  and  has 
two  main  bearings.  The  piston  is  provided  with  a  piston  rod 
and  crosshead.  The  front  end  of  the  cylinder  A  is  closed  and 
acts  as  the  air  compressor  to  furnish  the  scavenging  air  charge 
to  the  power  cylinder.  The  air  enters  the  compressor  through 
the  piston  valve  V. 


294 


OIL  ENGINES 


This  engine  employs  water  injection  to  control  the  cylinder 
temperature,  thus  preventing  preignition.  The  operator  should 
examine  the  cylinder  at  frequent  intervals  as  the  water  often 
scores  the  piston  and  cylinder.  The  question  of  water  injection 
is  fully  discussed  in  the  chapter  on  Water  Injection. 

Miiller  Ignition. — While  no  American  firm  has  adopted  this 
design,  it  is,  nevertheless,  of  interest.  This  is  especially  true 
since  some  claim  that  the  American  engines  using  the  Hvid 
principle  are  actually  operating  along  the  lines  covered  by  the 
Mtiller  patent. 

This  ignition  or  injection  method  has  simplicity  to  recommend 
it  since  it  does  not  require  either  an  air  compressor,  as  does  the 
Diesel,  or  a  fuel  injection  pump,  as  found  on  the  majority  of 


Raised  Position 


FIG.  231. — Muller    super    compression    ignition    device. 

semi-Diesels.  The  plan  which  is  illustrated  in  Fig.  231  is  as 
follows:  The  cylinder  head  is  provided  with  two  compartments. 
Into  one  of  these  runs  the  fuel  line  from  the  measuring  device 
controlled  by  the  governor.  This  cavity  is  connected  to  the 
engine  cylinder  by  means  of  a  needle  valve.  The  valve  is  better 
shown  in  the  drawing  to  the  right.  It  has  a  drilled  passage  and 
is  actuated  from  the  engine  camshaft,  the  timing  of  which  allows 
the  cylinder  to  be  in  communication  with  the  fuel  chamber 
during  the  engine  suction  and  compression  stroke.  During  the 
early  part  of  the  compression  stroke  the  fuel  is  deposited  in  the 
space  around  the  hollow  valve  stem.  At  the  end  of  the  com- 
pression stroke  this  valve  is  raised  and,  in  so  doing,  cuts  off 
the  communication  of  the  cylinder  with  the  portion  of  the  fuel 
chamber  above  the  surface  of  the  fuel  charge.  The  drawing 


THE  SEMI-DIESEL  OIL  ENGINE 


295 


illustrates  the  manner  by     which  the  valve  stem,  in  raising, 
brings  the  cross  passages  up  into  the  casting. 

At  the  moment  the  valve  a  is  raised  the  valve  b,  which  con- 
nects the  second  cavity  with  the  cylinder,  opens.  The  movement 
of  this  valve  allows  part  of  the  cylinder  air  charge  to  rush  into 
the  cavity,  reducing  the  cylinder  pressure.  The  pressure  now 
existing  within  the  cylinder  is  lower  than  the  pressure  of  the 
air  which  is  trapped  in  the  fuel  chamber.  This  pressure  differ- 
ence forces  the  oil  charge  through  the  valve  opening  into  the 


FIG.  232. — Muller  modified  ignition 
device. 


FIG. 


233. — Constructed      card 
Muller  modified  engine. 


of 


cylinder.  The  velocity  of  the  oil  through  the  passage  atomizes 
it  sufficiently  for  ignition  purposes. 

A  modification  of  this  idea  is  seen  in  Fig.  232.  In  this  design 
the  valves  are  dispensed  with  and  only  one  chamber  is  needed. 
In  operation  the  fuel  charge  is  deposited  during  the  compression 
stroke  in  the  fuel  compartment.  Between  this  and  the  cylinder 
is  interposed  a  disk  with  a  number  of  very  small  openings.  The 
fuel  rests  upon  the  disk  and  is  prevented  from  flowing  into  the 
cylinder  both  by  the  minuteness  of  the  openings  and  the  sur- 
face tension  of  the  oil. 

When  the  piston  reaches  dead-center,  the  existing  pressures  in 
the  cylinder  and  the  fuel  chamber  are  of  equal  value  while  the 
oil  rests  in  a  layer  between  these  two  air  charges.  As  the  piston 
moves  past  dead-center  on  the  outward  stroke,  the  increase  in 
the  engine  clearance  volume  causes  the  compression  in  the 
cylinder  to  drop  rapidly.  The  original  pressure  in  the  fuel 
chamber  then  injects  the  fuel  through  the  atomizer  holes  into 


296  OIL  ENGINES 

the  cylinder  where  the  temperature  is  high  enough  to  ignite  the 
charge  when  finely  divided.  A  card  from  an  engine  with  this 
ignition  would  probably  appear  as  shown  in  Fig.  233. 

Neither  of  these  designs  has  been  commercially  successful. 
Attention  is  called  to  the  similarity  of  the  card  from  the  Nordberg 
engine,  Fig.  226,  and  the  "constructed"  card  of  the  Miiller 
engine.  They  follow  the  same  general  outline  at  the  ignition 
point.  It  is  probable,  with  heavy  oils,  that  there  is  no  ignition 
in  the  cup,  the  compression  pressure  running  up  to  the  peak  d. 
The  piston  in  starting  outward  no  doubt  causes  the  air  charge 
in  the  cylinder  to  drop  in  pressure  to  the  point  b.  Due  to  the 
absorption  of  heat  from  the  hot  piston  head,  the  air  in  the  cup 
then  naturally  experiences  a  rise  in  pressure.  At  the  point  b 
the  air  pressure  in  the  cup,  which  would  have  remained  above  the 
value  d,  injects  the  oil  from  the  cup  into  the  cylinder  where 
ignition  occurs.  Nothing,  of  course,  is  known  positively  of  the 
actual  events  taking  place. 

De  La  Vergne  F.H.  Oil  Engine. — Another  type  of  the  semi- 
Diesel  engine  combines  the  Diesel  principle  of  atomizing  the  oil 
charge  by  means  of  a  stream  of  high-pressure  air,  and  the  hot- 
bulb  principle,  similar  to  that  used  on  the  low-pressure  engine. 
A  cross-section  of  the  De  La  Vergne  type  F.H.  engine  with  this 
combination  ignition  is  shown  in  Fig.  234.  In  general  outline 
and  in  many  details  it  closely  conforms  to  standard  horizontal 
Diesel  practice.  It  has  a  two-stage  air  compressor  A  for  the 
supply  of  the  injection  and  starting  air.  The  fuel  valve  of  the 
multi-cylinder  engines  closely  follows  standard  Diesel-engine 
design;  the  single- cylinder  engine  valve  is  somewhat  different 
in  action. 

In  operation  the  bulb  B  is  first  heated  by  a  torch  until  fairly 
hot.  The  fuel  pump  is  then  operated  by  hand  until  the  line  to 
the  injection  valve  is  filled.  The  engine,  which  has  already  been 
placed  in  the  starting  position,  is  turned  over  by  the  manipula- 
tion of  the  air-starting  valve.  After  two  air  charges  the  engine 
will  begin  firing.  The  fuel  from  the  pump  enters  the  body  of  the 
injection  valve  or  atomizer  where  it  comes  in  contact  with  the 
charge  of  high-pressure  air  from  the  air  compressor,  which  is 
mounted  on  the  engine  frame.  At  the  proper  moment  the 
needle  valve  is  opened,  and  the  combined  charge  of  air  and  fuel 
is  blown  into  the  cylinder  in  a  highly  nebulized  condition.  The 
fuel  charge  is  injected  slightly  before  dead-center.  The  charge, 


THE  SEMI-DIESEL  OIL  ENGINE  297 


FIG.  234a. — De  La  Vergne  type  F.H.  semi-Diesel  engine. 


FIG.  2346. — De  La  Vergne  type  F.H.  semi-Diesel  engine. 


298  OIL  ENGINES 

as  it  blows  across  the  combustion  chamber  into  the  vaporizer, 
burns  very  rapidly,  producing  a  sharp  peak  in  the  combustion 
line  on  the  indicator  card.  If  the  oil  is  light  in  gravity,  the  entire 
charge  is  consumed  instantaneously  since  it  is  injected  at  a  high 
velocity,  the  injection  occupying  only  an  infinitesimal  period  of 
time.  On  the  indicator  card,  this  action  produces  a  decided 
sharp  combustion  peak;  the  card  closely  resembles  a  card  from 
a  low-compression  or  const  ant- volume  engine.  If  the  fuel  is 
heavy,  24°  Baume*  crude  oil  for  example,  the  heavier  parts  are 
not  ignited  immediately  and  strike  the  hot  vaporizer  walls.  The 
hot  surfaces  vaporize  these  more  complex  hydrocarbons  with  a 
resultant  combustion.  It  then  follows  that  the  heavier  the  oil 
the  nearer  the  F.H.  card  approaches  a  card  from  a  true  Diesel. 
Figure  235  shows  a  card  where  such  a 
heavy  oil  was  used.  The  compression 
reached  275  pounds  while  the  maximum 
cylinder  pressure  approximated  600  pounds. 
FIG.  235.— Indicator  Since  with  light  oils  the  combustion  is  in 
card  type  F.H.  semi-  the  nature  of  an  explosion,  preignitions 

Diesel  engine.  ....  V   .          '  s  . 

will  be  present  if  the  injection  opening  is 

not  delayed.  To  allow  necessary  adjustments  of  the  fuel  in- 
jection timing,  the  needle  valve  rocker  arm  is  provided  with  a 
screw  arrangement  whereby  the  moving  of  the  roller  alters  the 
timing.  This  is  -plainly  seen  in  Fig.  234,  a  cross-section  of  a 
single-cylinder  F.H.  engine. 

It  is  problematical  whether  the  vaporizer  is  actually  required 
after  the  engine  is  in  operation  and  has  become  warmed.  The 
compression  pressure  of  280  to  300  pounds  should  be  sufficient  to 
vaporize  and  ignite  all  save  the  heaviest  of  crude  oils.  That  none 
of  the  light  fuel  oils  ever  reach  the  vaporizer  is  conclusively 
proven  by  the  absence  of  soot  or  carbon.  When  heavy  crude  is 
burned,  there  is  some  carbon  deposit,  but  not  more  than  is  usually 
found  on  the  piston  heads  of  Diesel  engines  when  supplied  with 
similar  oils.  Furthermore,  true  Diesel  engines  have  been  ob- 
served operating  with  a  compression  as  low  as  300  to  350  Ibs.  per 
sq.  inch,  in  cases  where  piston  rings  leaked  or  where  the  engine 
was  turning  over  very  slowly.  Under  such  conditions  the  Diesel 
would  ignite  every  charge  although  the  exhaust  was  somewhat 
cloudy.  After  an  engine  is  warmed  up,  a  compression  of  275  to 
300  Ibs.  per  sq.  inch  will  ignite  any  fuel  above  28°  Baume 
gravity. 


THE  SEMI-DIESEL  OIL  ENGINE 


299 


Fuel  Consumption.  F.H.  Oil  Engine. — In  fuel  consumption 
this  engine  approaches  the  Diesel  engine.  Figure  236  shows  the 
results  of  a  test  on  one  of  these  engines.  It  must  be  understood 
that  such  low  fuel  consumptions  are  not  usually  secured  in  opera- 
tion. If  a  full-load  consumption  of  .55  Ib.  per  brake  horsepower 
is  obtained,  the  engine  can  be  considered  in  excellent  condition. 


0.70 
0.60 

£0.50 

1 
W0.40 

1 

Pounds  Fuel  per  Brake  Hp. 

V 

^ 

£0.20 
0.10 

i 

3                          J4                          K                          «                     Tiull 

Load  Factor 
FIG.  236. — Teston  200  H.P.  De  La  Vergne  type  F.H.  semi-Diesel  engine. 

The  indicator  card,  Fig.  235,  is  somewhat  like  a  Diesel  card, 
though  the  combustion  line  is  not  a  constant-pressure  one.  The 
major  part  of  the  fuel  charge  explodes  almost  instantaneously, 
the  slow  combustion  occurring  with  the  heavier  parts  only. 

Fuel  Specifications.  F.H.  Engines. — Due  to  the  use  of  the 
vaporizer,  practically  all  fuels  above  16°  Baume*  can  be  consumed 
with  success.  If  the  cylinder  temperature  is  inadequate  for 
the  combustion  of  the  heavy  oils,  the  hot  surface  of  the  vaporizer 
will  "crack"  the  oils  and  complete  the  ignition.  With  the 
asphaltum-base  heavy  crude  oils,  a  deposit  of  carbon  will 
usually  be  found  in  the  vaporizer.  This  deposit  is  not  as  serious 
nor  as  extensive  as  in  the  low-pressure  engine,  and  the  cleaning 
need  be  performed  only  every  month  or  so. 

De  La  Vergne  Fuel  Pump. — On  the  multi-cylinder  F.H. 
engines  the  De  La  Vergne  Co.  employs  the  same  fuel  pump  and 


300 


OIL  ENGINES 


governor  as  shown  in  Fig.  143.  On  the  single-cylinder  units 
the  governor  is  the  same  while  the  operation  of  the  pump  is 
slightly  different. 


End  of  injection 
A  /    depends  on 
amount  of  fuel 


FIG.  237.— Valve  timing  De  La  Vergne  F.H.  semi-Diesel. 

Valve  Timing. — Figure  237  shows  the  valve  timing  for  the 
F.H.  engine.     The  timing  of  the  valves  does  not  differ  materially 


(Suction  and  discharge  valves  not  shown.) 
FIG.  238. — Price  combustion  chamber. 

from  standard  Diesel  practice.  The  period  of  fuel  injection 
varies  with  the  fuel  charge,  although  the  period  of  fuel  valve 
opening  is  constant.. 


THE  SEMI-DIESEL  OIL  ENGINE 


301 


Price  Ignition  System. — During  the  past  year  several  American 
engine  builders  have  begun  the  manufacture  of  semi-Diesel 
engines  with  the  Price  ignition  system  or  principle.  The  theory 


Section  a 


LJ 


Atomizer  Plug- 


Oil  Passage  around 
Valve  Stem. 


FIG.  239. — Price  engine  nozzle. 


of  operation  contemplates  the  use  of  a  compression  pressure 
of  200  Ibs.  per  sq.  inch.  Into  this  combustion  chamber  two 
streams  of  oil  are  injected.  These  two  streams  meet  and  com- 


302  OIL  ENGINES 

bustion  ensues  due  to  the  thorough  breaking  up  of  the  oil 
charges. 

The  combustion  chamber,  which  is  located  in  the  head  or 
separately,  as  the  builder  chooses,  is  along  the  lines  of  Fig.  238. 
The  two  injection  nozzles,  a  cross-section  of  which  appears  in 
Fig.  239,  are  placed  in  opposite  sides  of  the  chamber  in  an  in- 
clined position. 

The  cycle  of  events  is  as  follows:  The  engine,  which  so 
far  has  been  built  on  the  four-stroke-cycle  plan,  during  the 
suction  stroke  draws  in  a  cylinder  charge  of  pure  air.  On 
the  compression  stroke  this  air  is  compressed  to  a  final  pressure 
of  200  Ibs.  per  sq.  inch.  Six  degrees  before  dead-center  is  reached 
the  fue?l  pump  injects  an  oil  stream  through  the  two  nozzles. 
As  a  consequence  of  the  excellent  nozzle  design,  the  two  oil 
streams  enter  the  combustion  chamber  in  a  highly  divided  con- 
dition. These  two  jets  of  oil  particles,  traveling  at  a  high 
velocity,  meet  at  the  center  of  the  combustion  space  and  ignite. 
The  entire  combustion  is  instantaneous,  and  the  engine  may  be 
said  to  operate  on  the  "  constant-volume "  or  Otto  cycle.  The 
remainder  of  the  engine's  events  are  such  as  is  usual  in  a  four- 
stroke-cycle  engine. 

There  is  some  question  as  to  what  actually  occurs  on  injection. 
The  patentees  claim  that  the  atomization  at  the  nozzles,  combined 
with  the  further  breaking  up  of  the  fuel  at  the  junction  of  the 
two  streams  in  the  combustion  chamber,  is  sufficient  to  ignite 
the  fuel  at  the  temperature  corresponding  to  200  pounds 
compression,  which  would  be  in  the  neighborhood  of  265° 
Fahrenheit.  It  must  be  conceded  that  the  disturbance  taking 
place  when  the  oil  streams  meet  will  produce  a  thorough  inter- 
mingling of  the  air  and  fuel.  This  allows  each  minute  globule 
of  oil  to  be  surrounded  with  air  and  undoubtedly  contributes 
toward  a  very  complete  combustion  if  a  flame  be  present.  It 
does  not  appear  that  this  would  initiate  the  primary  ignition. 
Another  explanation  has  been  offered  which  sounds  logical. 

Evidently  the  engine  does  depend  on  the  absorption  of  heat 
from  the  combustion  walls  to  assist  the  ignition  since  the  engine 
will  not  fire  the  first  few  charges  unaided.  To  start  the  engine  a 
nickel-covered  anode  or  resistance  coil  is  used.  A  small  dynamo 
supplies  the  current  necessary  to  bring  this  coil  to  a  red, heat. 
On  starting  the  engine,  the  electric  current  is  thrown  on  to  the 
element,  and  the  oil  charge  is  ignited  exactly  as  in  a  hot-bulb 


THE  SEMI-DIESEL  OIL  ENGINE  303 

low-compression  engine.  When  the  combustion  chamber  is 
thoroughly  warmed  the  current  flowing  through  the  coil  is  dis- 
continued, although  the  coil  still  remains  in  the  combustion 
chamber.  Quite  likely  the  heat  of  combustion  maintains  it  in 
a  red-hot  condition,  although  at  a  much  lower  temperature  than 
when  the  electric  current  was  flowing.  It  would  appear  that 
some  heat  other  than  that  of  compression  is  required.  There 
also  seems  to  be  a  second  source  of  heat  that  might  assist  the 
process. 

The  opening  in  the  nozzle  tip  is  about  ^4-inch  in  diameter. 
If,  in  service,  a  fuel  consumption  of  16^  h.p.  per  gallon  is 
secured,  and  the  engine  operates  at  200  r.p.m.,  then  with  a 
100  h.p.  engine  the  fuel  consumed  per  minute  would  be 
}^0-gallon  or  23.1  cubic  inches.  At  200  r.p.m.,  operating 
on  the  four-stroke-cycle,  the  fuel  per  stroke  would  be  .23  cubic 
inch  per  effective  stroke.  The  injection  does  not  cover  more  than 
6  degrees;  the  injection  of  oil  through  the  two  atomizers  is  then 
at  the  rate  of  .02  cubic  inch  per  degree  of  revolution  or  1440 
cubic  inches  per  minute.  The  orifice  at  the  nozzle  tip  is  approxi- 
mately ^4-inch,  and  the  actual  injection  rate  through  the  nozzle 
opening  is  at  a  linear  velocity  of  60,000  feet  per  minute.  The 
weight  of  the  injection  charge  is  .0036  pound.  When  the  two  oil 
streams,  issuing  from  the  atomizers  at  this  rate  of  speed,  meet, 
it  may  be  considered  that  all  their  velocity  is  destroyed  and  the 
energy  developed  by  this  impact  appears  as  heat.  The  work 
done  would  be  Y^  M F*  or  560  foot-pounds.  The  heat  equivalent 
of  200  foot-pounds  is  0.70  B.t.u.  This  heat  is  absorbed  by 
the  oil  charge,  which  weighs  .0036  pound,  and  is  sufficient  to  raise 
the  temperature  of  the  oil .  charge  some  400°.  This  tem- 
perature increase  added  to  that  resulting  from  the  compres- 
sion is  high  enough  to  ignite  the  lighter  hydrocarbons,  which, 
in  turn,  ignite  the  heavy  particles.  The  rate  of  flame  propaga- 
tion would  be  rapid  since  the  oil  stream  is  atomized  in  a  very 
thorough  manner. 

Indicator  Card.  Price  Engine. — Figure  240  is  a  card  from  this 
engine  while  Fig.  241  is  a  distorted  card.  The  injection  begins 
at  6  degrees  ahead  of  dead-center  and  ceases  at  about  lj^-de- 
grees  before  dead-center. 

One  decidedly  attractive  feature  of  this  engine  is  the  high 
mechanical  efficiency.  This,  in  comparison  with  the  efficiency 
of  the  Diesel  engine,  can  be  attributed  mainly  to  the  elimination 


304 


OIL  ENGINES 


of  the  air  compressor,  which  usually  absorbs  from  7  to  10  per 
cent,  of  the  engine's  output. 


425 


Scale  200  Ibs. 


FIG.  240. — Full  load  indicator  card 
Price  engine. 


FIG.  241. — Distorted  card    Price 
engine. 


Test  on  Price  Engine. — Based  on  a  series  of  tests  conducted 
at  the  De  La  Vergne  Machine  Co.  plant,  before  a  committee  of 

0.90 


0.80 


£  0.70 


a  o.6o 


£0.50 


0.40 


0.30 


0.20 


0.10 


Mech. 


Eff. 


Full 
Load 


0  M  Yt 

FIG.  242.  —  Test  on  19  X24  Price  engine. 

naval  officials,   on  a  19X24  engine  using  the  Price  injection 
system,  the  following  report  was  submitted. 


THE  SEMI-DIESEL  OIL  ENGINE  305 

1.  The  fuel  economy  under  favorable  conditions  was  .395  pound  per 
brake  horsepower. 

2.  Fuel   economies  of  .42  pound  at  full  load  could  be  maintained 
indefinitely. 

3.  The  engine  could  be  put  in  operation  from  a  cold  condition  to  full 
load  at  full  speed  in  ten  seconds. 

4.  Any  fuel  from  15-degree  Mexican  crude  to  light  fuel  oil  could  be 
used. 

5.  At  all  loads  up  to  20  per  cent,  overload  the  exhaust  was  invisible, 
and  up  to  30  per  cent,  overload  the  exhaust  was  tolerable. 

6.  A  twenty-four-hour  test,  running  full  load  ten  minutes  then  stop- 
ping five  minutes,  proved  the  engine  to  be  safe  against  heat  stresses,  etc. 

7.  The  engine  could  be  stopped  twenty  minutes  and  started  again 
without  the  assistance  of  the  electrical  igniter. 

8.  A  mean  pressure  of  87  Ibs.  per  sq.  inch  with  respect  to  brake 
horsepower,    which    corresponds    to  approximately   100  Ibs.  per   sq. 
inch  mean  effective  pressure,  was  attained  with  clean  exhaust. 

9.  The  mechanical  efficiency  when  operating  above  three-quarters 
load  approximated  90  per  cent. 

Figure  242  presents  the  results  of  the  test,  showing  the  mechan- 
ical efficiency  and  the  fuel  per  brake  horsepower.  The  fuel 
consumption  compares  favorably  \\dth  the  economies  obtained 
from  Diesels  manufactured  in  the  United  States. 


20 


CHAPTER  XVIII 
LOW-COMPRESSION  OIL  ENGINES 

TYPES  OF  ENGINES.     DESIGN  OF  IGNITION  DEVICES 

General. — Although  the  crude  oil  engines  should  properly  be 
divided  into  the  three  classes:  Diesel,  or  high-compression; 
semi-Diesel,  or  medium-compression;  and  low-compression,  or 
vaporizer  engines,  there  is  a  strong  tendency  on  the  part  of 
many  builders  of  the  low-pressure  engines  to  call  their  product 
semi-Diesel  engines.  As  discussed  in  previous  chapters,  the 
word  "semi-Diesel"  does  convey  a  distinction  as  regards  the 
limits  of  compression  carried  on  the  engine.  Any  engine  whose 
compression  pressure  does  not  reach  at  least  250  Ibs.  per  sq.  inch 
and  which  depends  on  some  manner  of  hot  surface  for  the  vapori- 
zation of  the  fuel  before  ignition,  quite  properly  falls  within  the 
third  class  that  is  covered  by  the  term  "low-compression  engines." 
It  is  quite  possible  to  use  another  distinguishing  mark  whereby 
an  engine  may  be  correctly  labeled.  If  the  heat  is  received  at 
constant  volume,  the  engine  falls  in  the  third  class.  There  is 
no  theoretical  reason  why  a  high-compression  engine  should  not 
be  built  to  receive  the  heat  at  constant  volume.  It  is  impossible, 
practically,  since  the  pressure  of  explosion  would  run  so  high  as 
to  wreck  the  engine. 

Probably  the  greatest  volume  of  crude  oil  engine  business,  both 
in  number  of  units  and  in  horsepower,  is  in  the  low-pressure 
type.  Various  designs  of  this  class  of  engines  have  been  built 
in  this  country  for  fifteen  years  or  more,  and  the  total  number 
of  installations  is  large.  In  the  year  of  1916,  one  company  sold 
more  than  50,000  h.p.  in  sizes  ranging  from  10  h.p.  to  200 
h.p.  The  majority  of  these  units  are  installed  in  small  mills, 
factories  and  light  plants  where  the  attendants  are  usually 
unskilled.  It  speaks  volumes  for  the  simplicity  of  the  low- 
pressure  engines  that  they  can  run  day  in  and  day  out  under 
such  conditions.  It  is  this  simplicity  of  design  that  causes  the 
low-compression  engine  to  prove  actually  more  economical  than 
the  Diesel  in  total  operating  costs  in  a  great  many  plants, 

306 


LOW-COMPRESSION  OIL  ENGINES  307 

The  low-compression  engines  are  all  modificatio.ns  of  the 
original  Hornsby-Akroyd  engine.  While  this  engine  was  of  the 
four-cycle  principle,  only  one  manufacturer,  the  De  La  Vergne 
Machine  Co.,  still  adheres  to  the  four-stroke-cycle;  all  the  other 
manufacturers  adopted  the  two-stroke-cycle  as  being  simpler 
and  less  costly  to  build.  This  design  is  quite  similar  to  the  well- 
known  two-cycle  gasolene  engine  wherein  the  crankcase  is 
enclosed  and  acts  as  a  compressor  to  furnish  the  necessary  air 
to  scavenge  the  cylinder  of  the  burnt  charge,  although  in  the  oil 
engine  nothing  but  air  is  compressed  in  the  crankcase. 

Two -stroke -cycle  Engine.  Method  of  Operation. — Figures 
243  to  246  show  this  type  of  engine  with  the  crank  at  different 
angles  and  the  probable  process  of  mixing  and  firing  of  the  fuel 
charge.  It  is  impossible  to  ascertain  the  exact  state  of  affairs 
transpiring  in  the  cylinder,  and  these  figures  are  at  best  but  an 
attempt  to  give  the  most  probable  course  of  events.  In  Fig.  243, 
after  the  bulb  on  the  cylinder  has  been  heated  by  a  torch,  not 
shown,  the  fuel  is  sprayed  upon  the  red-hot  lip  of  the  bulb,  which 
projects  into  the  cylinder  space.  This  fuel,  on  igniting,  drives  the 
piston  forward.  At  a  point  in  the  stroke  of  the  piston,  as  indicated 
in  Fig.  244,  the  exhaust  port  is  uncovered  by  the  piston,  and  the 
burnt  gases,  which  still  have  considerable  pressure,  rush  out 
through  the  exhaust  pipe.  Figure  245  shows  the  air  port  un- 
covered by  the  piston  and  the  pure  compressed  air  from  the  crank- 
case  displacing  the  exhaust  gases  and  filling  the  cylinder  with  a 
fresh  air  charge.  In  Fig.  246  the  piston  has  compressed  this  air 
charge  to  from  70  to  120  pounds,  and  the  fuel  is  beginning  to 
spray  into  the  combustion  space.  The  above  sequence  of  action 
is  followed  in  all  two-stroke-cycle  surface  ignition  oil  engines, 
although  each  builder  has  certain  modifications  of  the  cylinder 
and  the  hot-bulb  design. 

Theory  of  Combustion. — The  operation  of  the  low-compression 
engine  is  based  on  the  fact  that  the  heavier  oils  will  not  self- 
ignite  in  the  presence  of  air  having  a  temperature  corresponding 
to  90  to  150  pounds  compression  pressure,  but  if  this  oil  strikes  a 
hot  surface  it  will  break  up  into  hydrocarbons  of  a  less  complex 
series;  in  other  words,  it  will  "crack."  These  light  oils  will 
vaporize  readily  and  will  ignite  at  a  temperature  much  lower 
than  is  required  to  ignite  the  heavy  original  oil.  Since  the  com- 
bustion of  the  fuel  involves  a  process  of  distillation  of  the  oil 
into  oils  of  lighter  gravity  before  burning,  the  time  necessary  for 


308 


OIL  ENGINES 


LOW-COMPRESSION  OIL  ENGINES  309 

complete  combustion  is  somewhat  longer  than  in  the  gasolene 
engine,  where  the  distillation  process  has  been  completed  at  the 
refinery,  or  in  the  Diesel  engine,  where  the  atomization  of  the 
heavy  oil  breaks  it  up  into  particles  small  enough  to  be  ignited 
by  the  high  temperature  of  the  compressed  air  charge.  Con- 
sequently, if  the  engine  speed  is  kept  above  200  r.p.m.,  the 
oil  must  be  injected  at  such  a  point  before  dead-center  as  to 
allow  it  sufficient  time  to  "crack,"  vaporize  and  burn.  At  200 
r.p.m.,  or  400  strokes,  the  time  consumed  in  making  a  power 
stroke  is  but  .15  second;  if  the  combustion  or  explosion  takes 
place  while  the  piston  covers  one-fifth  of  its  stroke,  the  time 
interval  is  only  .03  second.  To  allow  the  oil  time  to  undergo 
the  process  of  distillation  and  ignition  by  the  time  the  piston 
reaches  dead-center,  the  current  practice  is  to  begin  the  injection 
when  the  crank  is  30  degrees  or  more  ahead  of  rear  dead-center, 
allowing  the  injection  to  cease  before  the  piston  completes  this 
compression  stroke.  Since  practically  all  the  oils  used  contain 
a  percentage  of  lighter  constituents  that  will  vaporize  without 
going  through  the  process  of  "  cracking,"  and  burn  at  a  low  tem- 
perature, there  is  a  tendency  of  this  part  of  the  oil  to  ignite 
before  the  piston  reaches  dead-center  and  while  the  compression 
pressure  is  still  low.  To  avoid  this,  builders  depend  upon  one  of 
two  factors — they  either  design  the  combustion  chamber  in 
such  a  manner  as  to  allow  the  fresh  oil  vapors  to  remain  un- 
mixed with  the  fresh  air  until  the  piston  is  approximately  10 
degrees  from  dead-center,  or  they  provide  for  the  injection  of  a 
small  amount  of  water  at  each  cycle;  this  water  tends  to  keep 
down  the  temperature  in  the  cylinder  during  compression,  there- 
by precluding  the  preignition  of  the  lighter  portions  of  the  oil. 
Stratification  of  the  gases  and  air  as  aimed  at  in  the  first  method 
does  occur  in  some  designs,  although  it  is  far  from  successful  in  all. 
Ignition  Devices.  Hot-ball  Igniters. — Figure  247  shows  a  cross- 
section  of  the  ignition  device  used  on  one  engine  long  on  the 
market.  In  this  the  cylinder  head  is  a  plain  water-cooled  casting 
of  a  design  free  from  danger  of  heat  fracture.  To  this  head  is 
bolted  the  bulb  A  projecting  outward,  and  against  this  bulb  is 
placed  a  "spoon,"  or  lip,  B,  which  passes  through  an  opening 
in  the  head  and  projects  into  the  cylinder  cavity  (in  a  somewhat 
similar  design  the  spoon  is  integral  with  the  bulb) .  There  is  also 
a  heavy  block  or  combustion  chamber  C  fitting  into  the  cylinder 
space.  In  starting,  the  bulb  is  first  heated  to  a  high  temperature 


310 


OIL  ENGINES 


(not  red-hot)  by  a  torch.  As  soon  as  the  engine  is  started, 
either  by  cranking  or  by  using  an  air  starter,  the  fuel  pump, 
actuated  by  a  cam,  injects  a  charge  of  oil  through  the  nozzle  D 
immediately  above  the  hot  spoon.  This  oil,  on  striking  the 
spoon,  is  " cracked"  and  vaporized  and,  mixing  with  the  air 
charge,  is  ignited  by  the  temperature  of  the  compressed  air 
charge. 


FIG.  248.  FIG.  250. 

Ignition  devices  of  low-compression  oil  engines. 

Since  this  engine  operates  on  the  two-stroke-cycle/  using 
crankcase  compression,  the  air  charge,  as  it  blows  through  the 
air  ports,  is  unable  to  completely  scavenge  the  cylinder  of  all 
the  burnt  gases.  This  is  traceable  to  two  defects  that  are  in- 
herent in  all  two-stroke-cycle  engines.  One  of  these  defects  is 
the  volumetric  efficiency  of  the  crankcase  air  compressor. 
Due  to  the  volume  of  the  enclosed  crankcase  in  respect  to  the 
displacement  of  the  piston,  the  air  actually  passing  into  the 
cylinder  through  the  air  ports  is  not  equal  to  the  cylinder  volume 
by  any  means;  60  per  cent,  is  as  much  as  can  be  expected.  The 
second  defect  lies  in  the  inability  of  the  air  to  force  the  exhaust 
gases  out  through  the  exhaust  ports  without  mingling  with  these 


LOW-COMPRESSION  OIL  ENGINES  311 

gases  and  partially  escaping  into  the  exhaust  pipe.  Complete 
scavenging  of  the  cylinder  is  highly  desirable  in  order  thai;  suffi- 
cient oxygen  be  supplied  to  unite  with  the  oil.  On  the  other 
hand,  scavenging  of  the  hot  bulb  is  far  from  being  desirable;  in 
fact,  the  entire  scheme  of  operation  is  based  on  the  bulb  being 
charged  with  burnt  and  inert  gases  at  the  moment  the  fuel 
charge  is  injected  onto  the  "  spoon."  Consequently,  when  the 
fuel  is  vaporized  by  the  hot  spoon,  the  movement  of  the  air 
charge  in  front  of  the  advancing  piston  pushes  this  vapor  into 
the  bulb  where  it  mixes  with  the  inert  gases.  As  there  is  no  free 
oxygen  present  in  the  bulb,  there  can  be  no  explosion,  although 
the  temperature,  due  to  the  hot  bulb  and  to  the  compression 
pressure,  is  much  above  the  ingition  point. 

As  the  piston  advances  toward  the  head,  the  air  is  forced  into 
the  bulb,  where  it  mixes  with  the  oil  vapors  and  burns.  This 
stratification  of  the  oil  vapors,  the  burnt  gases  and  air  is  fairly 
successful  at  loads  up  to  about  three-quarters  of  the  engine's 
rating.  At  values  approaching  full  load,  the  beginning  of  the 
injection  of  oil  is  much  advanced,  and  the  amount  of  fuel  in- 
jected is  increased  to  such  a  value  that  the  bulb  does  not  accom- 
modate all  the  vapors.  As  a  result  part  of  the  fuel  charge 
mixes  with  the  pure  air  in  the  cylinder.  As  the  temperature 
existing  in  the  cylinder,  due  to  the  hot  bulb  and  to  the  compres- 
sion, is  above  the  ignition  point  of  the  " cracked"  light  oils, 
preignition  of  the  charge  frequently  takes  place,  resulting  in 
piston  pounding  and  loss  of  power.  In  order  to  avoid  the  pre- 
ignition, this  engine,  as  do  most  others,  makes  use  of  water  in- 
jection, whereby  at  each  cycle  a  small  quantity  of  water  is 
injected  into  the  cylinder,  reducing  the  compression  pressure 
and  the  temperature  existing  in  the  cylinder.  Because  of  the 
successful  stratification  of  the  gases  on  loads  below  three-quarters 
rating,  it  is  not  necessary  to  use  water  at  lower  load  values. 

The  conbustion  block  C  merely  serves  as  a  reservoir  of  heat 
to  assist  in  the  vaporizing  of.  the  fuel.  When  using  kerosene  or 
the  lighter  distillates,  this  block  gives  off  enough  heat  to  vap- 
orize the  oil  before  it  strikes  the  spoon;  with  heavy  fuels,  below 
30°  Baume  test,  most  of  the  charge  actually  strikes  the  spoon 
before  " cracking"  and  vaporizing. 

Oils  of  different  gravities  will  ignite  at  different  temperatures 
and  at  different  pressures.  In  order  to  make  the  time  of  igni- 
tion constant,  it  is  necessary  to  vary  the  compression  pressure 


312 


OIL  ENGINES 


according  to  the  character  of  fuel  oil  used.  To  do  this,  the 
Muncie  Engine  Co.  has  adopted  the  plan  of  inserting  steel  com- 
pression plates  behind  the  combustion  block.  By  varying  the 
number  and  thickness  of  the  plates  used,  it  is  possible  to  vary 
the  compression  from  90  to  140  pounds;  the  former  suitable  for 
kerosene,  the  latter  for  the  heavy  fuel  oils. 

The  hot  bulb  has  a  number  of  advantages.  Among  these  is 
the  fact  that,  being  made  with  fairly  thin  walls,  the  bulb  will 
break  in  case  of  any  dangerous  increase  of  pressure  in  the  cylin- 


FIG.  251. — Muncie  two-cycle  oil  engine  low  compression  type. 

der,  thereby  protecting  the  more  expensive  parts,  such  as  the 
cylinder  and  the  cylinder  head.  It  is  inexpensive  in  replacement 
cost,  quite  unlike  several  of  the  more  complicated  devices.  It 
has  another  advantage  that  is  of  material  assistance  in  operation. 
The  bulb  is  of  sufficient  size  to  contain  in  its  walls  a  great  amount 
of  heat.  The  heavier  the  load  the  greater  is  the  amount  of  heat 
absorbed  by  the  bulb.  This  increased  heat  serves  to  raise  the 
compression  temperature  to  a  higher  degree  than  usual.  The  oil 
burns  earlier  in  the  cycle,  and  by  suitable  adjustment  of  the  water 
injection  the  engine  can  be  made  to  fire  just  before  dead-center, 
giving  the  maximum  of  power.  The  bulb  is  open  to  objection 
because  of  its  tendency  to  fill  with  unburnt  carbon  in  cases  of 
leaky  fuel  injection  nozzles  or  heavy  overloads.  The  same  de- 
posits will  occur  where  leaky  piston  rings  allow  the  compression 


LOW-COMPRESSION  OIL  ENGINES  313 

to  escape  or  where  the  bulb  is  too  low  in  temperature.  This 
latter  may  be  due  to  cold  air  currents  striking  the  bulb  or  to  the 
cooling  water  in  the  cylinder  head  having  too  low  a  discharge 
temperature.  Carbon  deposits  in  the  bulb  are  invariably  accom- 
panied by  decrease  of  power.  The  carbon  frequently  is  the  cause 
of  preignitions.  Carbon  is  not  as  good  a  conductor  of  heat  as  are 
the  iron  walls  of  the  bulb;  consequently  the  carbon  will  become 
red-hot.  This,  of  course,  raises  the  cylinder  temperature  suffi- 
ciently to  ignite  the  oil  practically  at  the  instant  of  its  injection. 
In  cases  where  the  engine  preignites  even  with  the  normal  supply 
of  injection  water,  the  engineer  is  practically  safe  in  assuming 
that  the  bulb  is  full  of  carbon.  When  the  bulb  is  badly  car- 
bonized, the  easiest  way  to  cleanse  it  is  by  soaking  it  for  several 
days  in  a  bucket  of  lye,  following  up  with  a  thorough  washing  in 
kerosene.  It  pays  to  keep  at  least  two  extra  bulbs  on  hand. 

Figure  251  shows  a  view  of  the  Muncie  Oil  Engine,  which  makes 
use  of  the  hot-bulb  igniter  device. 

Hot-tube  Ignition. — A  second  ignition  device  is  that  shown 
in  Fig.  248.  Here  the  head  is  completely  water-cooled  and  has 
an  ignition  tube  projecting  into  the  cylinder  space.  This  tube 
may  be  either  fixed  or  removable.  If  fixed  in  place,  a  part  ex- 
tends beyond  the  outside  wall  of  the  head  and  is  heated  by  some 
manner  of  torch.  In  the  drawing  shown,  the  tube  is  removable 
and  is  first  heated  by  the  operator  at  some  convenient  flame  and 
is  then  placed  in  its  recess  and  clamped  into  place.  The  engine 
is  started,  and  the  fuel  is  then  injected  in  a  manner  similar  to 
that  of  the  hot-bulb  engine.  The  oil,  on  leaving  the  nozzle, 
strikes  the  red-hot  tube  and  of  course  " cracks"  and  vaporizes. 
This  oil  vapor  mixes  with  the  air  charge,  and,  as  soon  as  the  ad- 
vancing piston  has  raised  the  compression  temperature  high 
enough,  the  charge  is  fired  and  burns. 

In  a  hot-tube  design  the  scavenging  air  frees  the  cylinder  from 
almost  all  of  the  burnt  gases  since  there  is  no  pocket  or  bulb. 
Therefore  the  opportunity  for  stratification  of  the  vaporized  oil 
and  fresh  air  is  not  so  good  since  there  is  no  intervening  stratum 
of  inert  gases  to  separate  the  two;  as  a  result,  they  doubtless 
mix  immediately.  The  only  way,  then,  to  prevent  preignition  of 
the  charge  is  to  keep  the  temperature  down  until  the  piston  is 
practically  on  dead-center.  Since  the  hot  tube  contains  but  a 
small  amount  of  heat,  the  compression  temperature  and  pressure 
do  not  increase  as  rapidly  on  the  heavy  loads  as  they  do  in  an 


314  OIL  ENGINES 

engine  having  a  large  heating  element,  such  as  the  bulb.  Never- 
theless, to  keep  down  preignition  recourse  is  had  to  water  injec- 
tion even  at  fairly  low  loads. 

It  is  the  general  experience  that  all  engines  using  the  hot-tube 
arrangement  will  operate  better  on  lighter  oils  than  on  the 
heavier  fuel  oils — quite  the  opposite  of  the  hot-bulb  design  in 
this  respect.  The  hot-tube  engine  scavenges  better  than  the 
hot-ball  engine  and  consequently  shows  a  slightly  superior 
economy  at  the  heavy  loads  since  the  cylinder  is  charged  with 
virtually  pure  air,  insuring  a  better  combustion.  The  tube  is 
simple,  easy  to  replace  if  defective,  and  the  design  allows  the 
head  to  be  symmetrical  and  free  from  casting  strains. '  On  the 
other  hand,  it  does  not  present  a  large  surface  to  the  injected  oils 
and  often  does  not  give  off  enough  heat  to  vaporize  all  the  charge 
when  using  heavy  fuel  oils. 

The  operator  should  be  cautious  about  keeping  in  service  a 
tube  after  it  shows  any  considerable  amount  of  corrosion.  The 
tube  will  burn  in  two  eventually.  If  part  drops  into  the  cylinder, 
it  is  liable  to  cut  the  walls.  Some  engineers  have  a  practice  of 
heating  the  tube  at  a  fire  placed  some  distance  from  the  engine. 
They  often  wonder  why  the  engine  fails  to  fire  after  they  hur- 
riedly put  the  tube  into  place.  It  should  be  remembered  that 
the  radiation  of  heat  from  a  red-hot  bolt  is  very  rapid,  and  the 
tube  quite  likely  is  fairly  cold  by  the  time  it  is  locked  into  place. 
It  is  best  to  use  a  kerosene  or  gasolene  blow-torch  placed  not 
more  than  3  feet  from  the  engine.  The  Primm  Engine  makes 
use  of  a  device  along  these  lines.  See  Fig.  330. 

Hot-plate  Ignition. — Some  builders  have  adopted  modifi- 
cations of  the  hot-plate  design,  as  in  Fig.  249.  In  this  design 
a  bell-shaped  iron  casting  is  bolted  to  the  piston  head.  To 
start  the  engine,  the  cylinder  head  is  provided  with  a  small  hot 
tube,  which  is  heated  externally  by  a  torch.  The  fuel  is  injected 
through  the  nozzle  A,  which  is  located  in  the  center  of  the  cyl- 
inder head.  On  starting,  this  oil  will  drip  onto  the  starting  tube 
B  and  ignite.  After  a  few  revolutions,  the  bell  casting  or  hot 
plate  attains  a  sufficient  temperature  to  allow  the  torch  to  be 
removed. 

In  this  design  the  cylinder  is  practically  free  from  obstructions, 
and  the  scavenging  effect  of  the  air  charge  is  good.  On  the  com- 
pression stroke  the  air  charge  is  compressed  to  90  to  120  lb.,  and 
at  approximately  20  degrees  from  dead-center  the  fuel  is  in- 


LOW-COMPRESSION  OIL  ENGINES  315 

jected  through  the  nozzle.  The  hot  plate  remains  at  a  high 
temperature,  due  to  the  heat  absorbed  from  the  burning  fuel. 
Using  light  distillates,  the  temperature  existing  in  the  cylinder 
is  sufficient  to  vaporize  it  before  any  strikes  the  plate.  There  is 
no  attempt  at  stratification  since  the  fuel  charge  is  intermixed 
with  the  -air  immediately  upon  vaporizing.  Where  the  oil  used 
carries  much  lighter  portions  there  is  a  considerable  tendency 
toward  preignition  at  all  loads  above  one-half  engine  rating. 
This  preignition  is  especially  noticeable  on  heavy  loads  where 
the  fuel  injection  begins  very  early  in  the  stroke.  Consequently, 
water  injection  is  used  at  any  load  above  %  or  %  rating. 

The  hot-plate  design  is  good  in  many  respects.  It  is  better 
than  the  hot  tube  when  using  heavy  fuel  oil  since  it  provides 
more  vaporizing  surface.  It  is  not  liable  to  become  overheated 
or  burned  since  it  loses  part  of  its  heat  to  the  exhaust.  Further- 


FIG.  252. — Little  Giant  oil  engine  employing  hot-bolt  ignition. 

more,  as  the  air  enters  the  ports  it  blows  across  the  plate,  cooling 
it  to  a  considerable  extent.  This  is  an  advantage  at  full  loads, 
but  on  lighter  loads  this  cooling  effect  quite  often  results  in  the 
plate  not  igniting  the  fuel  charge.  It  is  doubtful  if  the  hot  plate 
helps  the  lubrication  of  the  cylinder;  certainly,  many  engineers 
are  in  constant  fear  of  faulty  lubrication  due  to  the  high  tempera- 
ture of  the  plate  burning  the  lubricating  oil  off  the  cylinder  walls 
on  the  compression  stroke.  There  is  another  little  trouble  that 
must  be  guarded  against.  The  plate  may  fracture,  and  the 
broken  parts,  becoming  wedged  in  the  exhaust  ports,  will  ruin 
the  piston.  This  probably  happens  but  seldom;  nevertheless, 
it  is  worth  the  attention  of  the  careful  engineer.  If  a  battering 
.sound  is  heard  in  the  cylinder,  it  is  advisable  to  stop  the  engine 
and  see  if  the  plate  is  intact. 

Figure  252  shows  a  cross-section  of  the  Chicago  Pnuematic 


316  OIL  ENGINES 

Tool  Co.'s  "Little  Giant,"  an  engine  making  use  of  a  modification 
of  this  principle. 

Separate  Combustion  Chamber. — To  attain  fair  stratification 
or  separation  of  the  oil  vapor  and  air  charges,  the  ignition  device 
shown  in  Fig.  250  has  been  brought  out.  This  combustion 
chamber,  in  some  respects,  is  a  reversion  to  the  original  Hornsby- 
Akroyd  design.  With  this  construction  a  cavity  is  cast  in  the 
head  with  the  open  end  outward,  while  a  small  opening  acts  as  a 
port  of  communication  between  the  cavity  and  the  engine  cylin- 
der. To  complete  the  combustion  chamber  a  semi-spherical 
casting  is  held  against  the  combustion  chamber  by  means  of  a 
retaining  collar,  not  shown.  The  cylinder  head  is  completely 
water-cooled,  consequently  the  half  of  the  combustion  chamber 
formed  in  the  head  is  also  water-cooled ;  the  combustion  chamber 
cap  is  partially  water-cooled  by  means  of  a  cored  passage  around 
its  juncture  with  the  cylinder  head.  The  oil  is  sprayed  in  at  the 
side  of  the  chamber. 

To  start  the  engine,  the  starting  tube  A  is  first  heated  until  it 
is  red-hot.  The  fuel  is  then  injected  by  means  of  a  hand  lever 
operating  the  fuel  pump.  It  is  usually  necessary  to  give  the 
pump  several  strokes.  Then  the  engine  is  pulled  back  against 
the  compression  until  the  piston  almost  reaches  dead-center, 
whereupon  the  fuel  explodes  and  the  engine  turns  over.  In 
cases  of  the  larger  size  engines  an  air  starter  is  used;  it  is  neces- 
sary to  turn  the  engine  over  two  or  three  times  with  the  air 
starter  before  the  fuel  will  ignite.  After  the  engine  has  run  a  few 
minutes,  the  vaporizer  or  combustion  chamber  absorbs  enough 
heat  to  fire  the  fuel  without  the  assistance  of  the  torch. 

The  scavenging  air  frees  the  cylinder  of  at  least  75  per  cent. 
of  the  exhaust  gases.  Owing  to  the  restricted  opening  into  the 
combustion  chamber,  it  remains  filled  with  inert  gases  during 
the  compression  stroke.  The  fuel  is  injected  directly  into  the 
combustion  chamber,  when  the  piston  is  from  20  to  40  degrees 
from  dead-center  and  the  temperature  of  the  uncooled  chamber 
cap  is  sufficient  to  vaporize  it.  When  the  piston  approaches  the 
head,  the  air  is  forced  into  the  chamber  and,  uniting  with  the  oil 
vapor,  causes  combustion.  The  piston  leaves  but  a  slight  clear- 
ance in  the  cylinder,  and  all  the  combustion  occurs  in  the  cham- 
ber; the  hot  gases,  passing  through  the  narrow  opening,  act  oir 
the  piston  face.  This  design  is  one  of  the  best  used.  The  fuel 
being  burnt  outside  the  cylinder,  there  is  but  little  danger  of 


LOW-COMPRESSION  OIL  ENGINES  317 

unburnt  carbon  deposits  cutting  the  cylinder  walls.  As  a  result, 
the  amount  of  lubrication  necessary  is  considerably  less  than  in 
the  case  of  a  hot-tube  or  hot-plate  engine.  Since  the  combustion 
chamber  is  filled  with  burnt  gases  when  the  fresh  oil  charge  is 
injected,  there  can  be  no  ignition  until  the  piston  forces  the  pure 
air  charge  into  the  combustion  chamber.  Having  the  advantage 
of  being  partly  water-cooled,  the  combustion  chamber  seldom 
becomes  overheated.  However,  on  full  loads,  the  amount  of 
heat  absorbed  by  the  walls  is  so  considerable  as  to  cause  the  cap 
to  get  cherry  red.  To  reduce  this  temperature  the  cap,  as  already 
mentioned,  has  a  small  cooling  space,  and  the  operator  must 
open  the  cooling-water  connection.  This  sudden  chilling  quite 
often  causes  the  cap  to  break;  in  fact,  this  is  the  one  serious 
drawback  to  this  design  of  combustion  chamber.  Where  fuel 
oil  of  30°  Baume  or  lower  is  used,  it  is  absolutely  neces- 
sary that  this  cap  be  allowed  to  bcome  cherry  red  in  order 
that  all  this  heavy  oil  be  vaporized.  With  the  light  distillates 
the  oil  will  preignite  if  the  cap  gets  too  hot.  If  it  is  cherry  red, 
the  oil  vapors  will  absorb  so  much  heat  that  their  volume  will 
exceed  that  of  the  chamber,  and  some  of  the  vapor  will  enter 
the  cylinder  and,  uniting  with  the  air,  explode.  Each  engine  has 
certain  characteristics  of  its  own;  the  engineer  must  experiment 
and  ascertain  under  what  temperature  condition  his  engine  best 
handles  the  fuel  used. 

In  the  water  connections  to  the  cooling  ring  it  is  imperative 
to  have  an  atmospheric  vent.  If  this  is  not  provided,  steam  will 
be  trapped  in  the  water  space  and  all  cooling  effect  prevented. 
The  cap  continues  to  become  more  heated  and  ultimately  will 
give  way. 

As  there  is  good  stratification,  the  builders  have  eliminated 
the  water  injection  feature.  Without  water  injection  the  engine 
operates,  on  the  partial  loads,  up  to  about  80  per  cent,  of  normal 
rating,  without  preignition;  at  full  load  the  oil  charge  is  great 
enough  to  allow  some  of  it  to  escape  into  the  cylinder,  resulting 
in  preignition.  This,  of  course,  applies  to  engines  where  the 
fuel  used  is  of  high  gravity,  since  with  such  oil  the  compression 
pressure  is  sufficient  to  cause  ignition,  being  about  160  pounds. 
This  type  of  engine  operates  best  on  distillates  above  32°  Baume. 
The  temperature  of  the  combustion  chamber  is  not  sufficient 
to  completely  vaporize  the  heavy  oils,  such  as  24°  fuel  oil 
Consequently,  using  this  latter  fuel,  there  is  always  a  heavy 


318  OIL  ENGINES 

deposit  of  carbon  in  the  combustion  chamber,  requiring  frequent 
cleaning.  The  fuel  economy,  compared  with  other  low-pressure 
engines,  is  good.  This  is  due,  in  part,  to  the  fact  that  there  is  not 
the  thermal  loss  which  occurs  with  water  injection.  It  might 
be  well  to  call  attention  to  the  fact  that  an  engine  with  a  given 
cylinder  volume  will  not  develop  as  great  a  horsepower  without 
water  injection  as  it  will  with  water  injection.  This  is  based 
solely  on  the  fact  that  water  injection  will  prevent  preignition, 
which  occurs  in  any  engine  pulling  a  heavy  load.  It  is  customary 
to  find  an  engine  given  a  lower  rating  when  the  water  feature 
is  abandoned.  An  English  firm  reduced  the  ratings  of  their 
engines  25  per  cent,  when  they  gave  up  the  water  injection.  An 
American  engine  builder,  when  first  going  into  the  crude-oil 
engine  business,  used  the  water  feature.  This  was  abandoned 
as  a  result  of  a  conclusion  that  it  possessed  certain  objectionable 
characteristics.  On  changing  the  design  to  eliminate  the  water, 
the  ratings  were  changed  approximately  20  per  cent.  The 
engine  then  developed  only  the  normal  rated  output  without 
preignition,  while  the  first  design  easily  developed  30  to  40  per 
cent,  overload  with  the  same  size  cylinder  and  the  same  speed. 

This  design  is  used  on  several  English  engines,  notably  the 
Fetter,  as  well  as  on  American  engines.  Figure  253  is  a  view  of 
the  Fairbanks-Morse  vertical  engine,  which  makes  use  of  this 
device.  The  Bolinder  engine  also  uses  a  device  along  the  same 
lines. 

As  mentioned  previously,  these  engines,  using  the  combustion 
chamber,  employ  a  nickel  starting  tube.  This  tube  heats  more 
than  the  cast-iron  head.  The  oil  charge  is  so  directed  as  to 
strike  the  tube  and  vaporize  readily.  A  second  nickel  tube  is 
sometimes  used  in  order  to  positively  vaporize  and  fire  the  heavy 
crude  oils.  This  tube  has  a  cavity  opening  into  the  chamber, 
and  the  oil  enters  this  opening  and  is  vaporized  by  the  hot  walls 
of  the  tube.  This  tube  has  a  tendency  to  coke  up  and  will  soon 
lose  its  usefulness.  Each  time  the  cap  is  removed,  the  tube 
should  be  cleaned  out. .  In  case  of  a  burned  tube,  it  can  be 
removed  by  unscrewing  it  from  the  inside  of  the  cap,  using  a 
chisel  driven  into  the  tube  cavity.  If  an  extra  tube  is  not 
available,  an  iron  bolt  about  2  inches  long  will  be  about  as  ser- 
viceable since  it  will  project  into  the  chamber  and  the  fuel 
will  strike  it,  or  at  least  in  its  close  vicinity. 

A  modification  of  this  design  is  used  on  the  Fairbanks-Morse 


LOW-COMPRESSION  OIL  ENGINES 


319 


vertical  engines.  In  this  construction  the  entire  combustion 
chamber  is  water-cooled  with  the  exception  of  a  flat  cover-plate. 
By  this  means  there  is  no  overheating  at  full  load,  as  the  water- 
cooling  keeps  the  temperature  within  reasonable  limits;  in  fact, 
on  partial  loads,  the  cooling  is  too  successful,  resulting  in  some 
of  the  fuel  charges  not  igniting  at  all.  This  is  especially  notice- 
able when  using  heavy  oils.  As  a  result,  if  the  engine  runs  on 


FIG.  253. — Fairbanks-Morse  type  "Y"  oil  engine.^ 

partial  loads  very  much  of  the  time  there  is  a  decided  tendency 
toward  heavy  carbon  deposits  both  on  the  combustion  chamber 
walls  and  on  the  flat  cover-plate.  If  this  carbon  is  not  cleaned 
out,  the  engine  will  run  very  hot  on  heavy  loads  and  will  pre- 
ignite  very  pronouncedly,  and  the  exhaust  will  show  very 
smoky.  The  carbon  will  work  loose  and  drop  into  the  cylinder 
cavity.  When  it  is  recalled  that  this  deposit  becomes  as  hard 
as  iron,  it  is  easy  to  see  how  quickly  a  little  carbon  will  ruin  the 
cylinder  walls. 

Since  the  combustion  chamber  is  cooled  by  the  same  water 
that  flows  around  the  cylinder  walls,  there  is  no  way  of  varying 


320 


OIL  ENGINES 


the  cooling  effect  on  the  head  in  accordance  with  the  load  carried. 
In  a  few  installations  engineers  have  made  the  combustion  cham- 
ber cooling  system  separate  from  the  jacket,  with  very  desirable 
results. 

The  casting  is  rather  complicated,  and,  as  a  result,  there  are 
severe  shrinkage  stresses  existing  in  the  head;  these  strains, 
augmented  by  the  explosion  stresses,  frequently  cause  fractures. 
Some  cases  of  fractured  heads  are  directly  traceable  to  the  engi- 
neer's negligence;  he  starts  his  engine  without  first  having  the 
cooling  water  running.  Afterward,  when  this  neglect  is  noticed, 
the  sudden  impinging  of  the  cold  water  on  the  hot  sides  of  the 
head  breaks  it. 


FIG.  254. — Buckeye  Barrett  oil  engine  combustion  chamber. 

Figure  254  outlines  an  ignition  bowl  employed  on  the  Buckeye- 
Barrett  engine  that  is  in  principle  the  same  as  Fig.  250.  In  this 
case  the  interior  of  the  bowl  is  spherical  shaped,  with  the  upper 
part  cut  away,  affording  an  entrance  to  the  cylinder.  This 
casting  is  cylindrical  in  outer  form  and  fits  into  the  cylinder 
head,  which  is  entirely  water-cooled  as  is  also  the  cylinder  head- 
cap.  The  bowl  is  heated  by  a  starting  torch,  blowing  through 
the  passage  A.  Since  it  has  no  starting  tube,  more  time  is  re- 
quired to  start  as  the  bowl  heats  slowly.  The  design  contem- 
plates the  isolation  of  the  vaporized  fuel  charge  in  the  bowl  until 
dead-center  has  been  reached,  when  the  air  charge  entering  the 
bowl  furnishes  the  necessary  oxygen  for  combustion. 

Operation. — In  starting  an  engine  using  any  of  these  devices, 
the  operator  should  not  pump  too  much  oil  in  by  hand  before 


LOW-COMPRESSION  OIL  ENGINES  321 

starting.  There  are  two  objections  to  this  all  too  common  prac- 
tice. First,  the  amount  of  oil  vaporized  will  be  so  great  as  to  fill 
part  of  the  cylinder  volume,  and  the  extra  quantity  of  gas  to  be 
compressed  will  raise  the  compression  pressure  high  enough  to 
explode  the  charge  early  in  the  compression  stroke.  The  engine 
will  then  run  backward  until  stopped  by  the  explosion  on  the 
next  stroke.  This  is  not  advisable,  especially  when  pulling  a 
direct-current  dynamo.  The  second  objection  lies  in  the  heavy 
carbon  deposits  that  this  excess  fuel  charge  causes.  Experiment 
will  soon  reveal  just  how  much  of  an  initial  oil  charge  must  be 
injected. 


ri-M 


FIG.  255. — Bessemer  oil  engine. 

Figure  255,  cross-section  of  the  Bessemer  oil  engine,  illustrates 
an  ignition  bowl  that  operates  on  the  same  general  principles  as 
does  the  above.  In  this  case,  however,  a  starting  tube,  which  is 
cast  on  the  bowl,  is  used. 

Four-stroke-cycle  Engine  Ignition  Device. — Very  few  builders 
have  adopted  the  four-stroke-cycle  in  their  low-pressure  engine. 
The  only  prominent  American  firm  doing  so  has  adopted  the 
ignition  device  illustrated  in  Fig.  256.  In  this  design  the  cylinder 
head  is  water-cooled  and  has  embodied  in  it  the  engine  combus- 
tion chamber.  As  the  drawing  shows,  the  admission  and  exhaust 
valves  are  in  the  top  of  this  combustion  chamber.  The  lower 
part  of  the  chamber  is  formed  by  a  separate  uncooled  cup.  This 
cup  or  cover  is  heated  by  a  torch,  and  the  vaporization  and  igni- 
tion of  the  fuel  proceed  in  a  manner  quite  like  that  in  the  design 
ot  the  two-cycle  engine,  Fig.  250. 

21 


322 


OIL  ENGINES 


The  four-cycle  design  insures  a  cylinder  charge  of  pure  air  as 
the  exhaust  stroke  of  the  piston  dispels  all  the  burnt  gases.  The 
scavenging  is  usually  more  than  is  desired.  In  many  cases  the 
inertia  of  the  moving  gases  tends  to  clear  the  combustion  cham- 
ber of  the  burnt  charge.  This  fills  with  fresh  air  on  the  suction 
stroke,  and  the  oil,  then,  is  injected  into  a  mass  of  pure  air.  The 
proneness  toward  preignition  is  present  even  on  loads  below 
engine  rating.  The  intense  heat  radiated  from  the  hot  cup  is 
partially  absorbed  by  the  overhead  valves.  The  engineer  should 


FIG.  256. — De  La  Vergne  D.H.  engine  vaporizer  or  igniter. 


examine  the  valves  periodically  and  regrind  as  often  as  necessary. 
In  case  of  loss  of  power  it  is  usually  safe  to  figure  that  the  valves 
are  leaking.  If  the  water  contains  much  mineral  matter,  a  solu- 
tion of  muriatic  acid  should  be  used  occasionally.  Due  to  the 
form  of  the  cooling  space,  the  sediment  is  liable  to  deposit  around 
the  port  into  the  cylinder.  This  is  a  dangerous  condition,  for 
fire  cracks  will  develop,  resulting  in  leakage. 

General. — From  the  foregoing  it  is  apparent  that  there  are  a 
number  of  different  cylinder  head  designs,  although  all  these  igni- 
tion devices  are  based  on  the  process  of  vaporization  and  ignition, 
by  temperature,  of  the  fuel  charge. 

The  first  and  all-important  factor  in  successful  operation  of  any 
of  these  hot-igniter  engines  is  to  keep  the  ignition  device  clean. 
The  operator  should  have  an  extra  part  on  hand  and,  when  cleaning 


LOW-COMPRESSION  OIL  ENGINES  323 

one,  should  use  the  spare  part.  Soaking  the  carbonized  igniter  in  lye 
for  a  few  days  and  ending  up  with  a  thorough  washing  in  kerosene 
will  clean  it  very  satisfactorily.  If  the  engine  tends  to  preignite 
on  ordinary  loads,  inserting  copper  gaskets  between  the  head  and 
bulb,  or  the  head  and  cylinder  casting,  thereby  increasing  the 
clearance  volume,  will  probably  relieve  this.  If  the  engine,  on 
starting,  blows  through  the  joint  between  the  head  and  bulb,  too 
much  pressure  should  not  be  used  in  tightening  up  the  studs. 
The  engineer  should  bear  in  mind  that,  as  soon  as  the  engine 
warms  up,  this  leakage  will  cease. 


CHAPTER  XIX 
LOW-PRESSURE  ENGINE  CYLINDERS 

Cylinder  Designs. — The  cylinders  used  on  two-cycle  low-pres- 
sure engines  may  well  be  separated  into  two  classes — those  having 
the  crankcase  enclosed  to  act  as  a  scavenging  air  compressor, 
and  those  which  make  use  of  the  front  end  of  the  cylinder  for 
the  same  purpose.  However,  the  general  designs  of  these  two 
are  quite  similar,  the  chief  difference  being  in  the  extra  length 
of  cylinder  employed  in  the  second  class. 

Figure  251  is  a  typical  horizontal  cylinder  where  crankcase 
compression  is  used.  It  consists  of  a  simple  casting  with  the 
necessary  cored  passages  for  the  exhaust  ports,  air-intake,  etc. 
This  design  is  closely  followed  by  a  number  of  builders. 
The  details  in  which  they  vary  are  usually  the  shape  and 
extent  of  the  air  ports  and  the  position  of  the  exhaust  ports. 

To  attain  a  good  scavenging  effect  with  the  air  charge,  it  is 
necessary  to  have"  the  air  passages  enter  the  cylinder  at  an  angle 
so  as  to  direct  the  air  toward  the  cylinder  head,  and  then  it  is 
not  necessary  to  rely  exclusively  on  the  deflection  plate  on  the 
piston.  It  is  about  as  harmful  to  have  too  much  air-port  area 
as  too  little.  Some  builders  attempt  to  place  the  ports  as  far 
around  the  cylinder  girth  as  the  exhaust  passage  permits — 
planning,  in  this  way,  to  obtain  a  better  scavenging  effect.  How- 
ever, as  the  air  enters  the  many  ports  it  tends  to  focus  on  the 
center  of  the  cylinder  head,  causing  eddy  currents  that  do  but 
little  good.  Furthermore,  with  a  decreased  port  area  the  air 
velocity  is  higher  with  a  consequent  better  cleansing  of  the 
cylinder. 

The  majority  of  engines  are  arranged  to  have  the  piston  un- 
cover the  exhaust  ports  before  the  air  ports  are  opened;  in  this 
way  a  greater  part  of  the  gases  pass  out  of  the  cylinder  before 
the  air  enters.  This  decreases  the  amount  of  air  required,  or 
the  case  is  better  stated  by  saying  that  the  available  air  supply 
is  used  to  better  advantage.  At  the  same  time,  it  allows  the  air 
pressure  to  be  less  since  the  gases  in  the  cylinder  would  be  at 
practically  atmospheric  pressure  when  the  air  starts  to  blow 

324 


LOW-PRESSURE  ENGINE  CYLINDERS  325 

through.  In  many  installations  the  exhaust  falls  below  atmos- 
pheric pressure,  owing  to  the  inertia  of  the  column  of  exhaust 
gases  forming  a  vacuum  at  the  engine.  To  obtain  this  the 
exhaust  pipe  must  be  of  a  length  that  allows  the  gases  to  leave, 
the  open  end  at  the  moment  the  piston  uncovers  the  exhaust 
port  for  the  discharge  of  the  succeeding  charge. 

Cylinder  with  Front-end  Compression. — Figure  255  is  a  cross- 
section  of  a  cylinder  wherein  the  front  end  is  enclosed  and  acts 
as  the  scavenging  air  compressor,  in  place  of  the  enclosed  crank- 
case.  The  layouts  of  the  air  and  exhaust  ports  are  quite  like 
the  cylinder  shown  in  Fig.  251. 


FIG.  257. — Cylinder  with  removable  liners  De  La  Vergne  D.H.  low  compression 
"t  oil  engine. 

Cylinder  with  Removable  Liner. — Figure  257  shows  a  design  of 
cylinder  that  follows  accepted  gas  and  high-compression  oil  en- 
gine practices.  The  cylinder  jacket  is  cast  integral  with  the 
engine  frame  while  the  cylinder  itself  is  a  removable  cast-iron 
liner  pressed  into  the  jacket.  At  the  rear  or  cylinder-head  end 
a  flange  rests  in  a  recess  in  the  jacket,  while  the  other  end  is 
sealed  against  water  leakage  by  packing  rings.  The  liner,  by 
this  method-  of  anchorage,  is  free  to  expand  lengthwise.  The 
design  has  much  to  commend  itself.  It  makes  cylinder  replace- 
ments lower  than  in  the  case  of  the  combined  jacket  and  cylinder; 
and  there  is  but  little  danger  of  leakage,  even  though  many 
engineers  are  prejudiced  because  of  this  remote  possibility. 


326 


OIL  ENGINES 


Vertical  Engine  Cylinder. — Figure  258  is  that  of  the  cylinder 
used  on  several  makes  of  vertical  engines.  It  is  a  one-piece 
casting  of  simple  design,  having  the  air  passage  formed  in  the 
casting.  An  attractive  feature  is  the  hand  plate  at  the  side. 
Opening  this  allows  the  piston  pin  and  brass  to  be  inspected, 
through  a  like  opening  in  the  piston.  It  is  also  handy  to  see 
if  the  piston  rings  are  fast  in  their  grooves.  This  cylinder  design 
is  employed  on  the  Fairbanks-Morse  engines  and  is  similar  to 
that  of  the  Bolinder  and  of  the  Mietz  and  Weiss  engines. 


O 


FIG.  258. — Vertical  engine  cylinder. 

Thickness  of  Cylinder  Walls. — The  design  of  cylinders,  as 
well  as  of  all  other  parts,  is  strictly  a  matter  that  pertains  to 
engine  manufacturing,  and  not  to  engine  operation.  Even  so,  an 
operator  should  see  that  certain  precautions  have  been  observed 
in  order  that  he  may  be  assured  a  satisfactory  machine.  In  all 
these  designs  it  is  well  for  the  operator  or  purchaser  to  note  if 
the  cylinder  walls  are  thick  enough  to  allow  for  at  least  one  re- 
boring.  The  walls  should  be  calculated  from  the  formula  for 
a  cylinder  with  thin  walls. 


where 
t 
p 


t 


thickness  of  cylinder  wall. 
maximum  explosion  pressure. 


LOW-PRESSURE  ENGINE  CYLINDERS  327 

D  =  diameter  of  cylinder. 
S    =  allowable  fibre  stress. 
k    =  constant  to  allow  for  reboring, 
its  value  depending  on  cylinder  diameter. 

Diameter  of  cylinder  6  to  11  in.         12  to  20  in. 

Value  of  k 


It  is  common  practice  with  low-pressure  engines  to  cast  the 
cylinder  liners  with  the  jacket.  It  is  undoubtedly  the  most  sat- 
isfactory method  in  engines  of  moderate  size.  It  is  very  easy 
to  provide  material  for  reboring  and  at  the  same  time  keep  the 
thickness  down  to  a  value  where  the  cooling  effect  of  the  water 
is  sufficient.  It  is  seldom  that  the  cylinder  liner  develops  a  frac- 
ture, and  so  the  replacement  cost  may  be  forgotten.  As  regards 
the  reboring  feature  a  few  builders  are  following  the  practice  of 
selling  a  new  piston,  oversize,  and  a  rebored  cylinder,  taking  as 
part  payment  the  worn  cylinder;  this  cylinder  is  then  rebored  at 
the  factory  and  sold  to  the  next  customer. 

Reboring  a  Cylinder.  —  Frequently  the  cost  of  a  new  cylinder 
is  so  excessive  that  the  cheapest  procedure  is  to  rebore  the  worn 
cylinder.  If  the  engine  cylinder  be  under  10  inches  in  diameter, 
the  job  of  reboring  can  be  done  by  almost  any  machine  shop. 
It  is  not  necessary  that  the  shop  have  a  horizontal  boring  mill. 
The  cylinder  can  be  clamped  onto  the  carriage  of  a  large  lathe, 
and  a  boring  bar  made  of  a  piece  of  shafting  with  a  boring  tool 
clamped  in  a  slot  cut  in  the  shafting.  This  can  be  placed  between 
centers  on  the  lathe  and  be  driven  by  a  lathe  dog.  No  matter 
whether  the  job  be  done  on  a  boring  mill  or  lathe,  a  roughing  cut 
should  be  first  taken,  followed  up  by  a  light  finishing  cut;  the 
feed  should  be  fine  enough  to  allow  the  surface  to  be  free  from 
any  undesirable  tool  marks.  To  complete  the  reboring  job  a 
block  of  brass  or  cast  iron  should  have  one  side  turned  to  the 
cylinder  radius;  wrapping  fine  emery  cloth  about  this  block,  a 
vigorous  rubbing  will  make  the  cylinder  smooth  as  glass  and  pre- 
serve the  curvature.  In  reboring  a  worn  cylinder,  extreme  care 
should  be  used  in  getting  the  center  line.  The  average  cylinder 
has  the  flange,  where  it  is  bolted  to  the  frame,  turned  square 
with  the  original  cylinder  center  line.  This  flange  should  be 
used  as  a  guidance  in  lining  up.  On  large  engines  the  cylinder 
cannot  be  handled  on  a  lathe.  The  best  procedure  is  to  have 
the  cylinder  rebored  by  some  firm  that  makes  a  specialty  of 


328  OIL  ENGINES 

reboring  cylinders.  This  can  be  done  by  means  of  a  portable 
boring  mill  without  removing  the  cylinder  from  the  engine. 

Causes  of  Cylinder  Wear. — The  question  of  cylinder  wear  on 
the  low-pressure  oil  engine  is  very  vital.  Probably  this  is  raised 
more  than  any  other  where  the  purchase  of  such  an  engine  is 
being  considered.  Looking  back  into  the  history  of  the  develop- 
ment of  this  type,  one  must  concede  that  cut  and  scored  cylinders 
figure  quite  prominently.  A  number  of  things  were  contributory 
causes.  Water  injection  was  blamed  by  many;  lack  of  lubrica- 
tion, poor  grade  of  cast  iron  used  in  making  the  cylinder,  and 
lack  of  cooling  effect  by  others.  Water  injection  may  have  some 
effect  where  kerosene  is  used  or  where  the  fuel  oil  is  high  in  sul- 
phur, but  for  the  fuel  or  distillate  oils  ordinarily  used  it  is  open 
to  dispute  as  to  whether  the  water  does  cause  cutting.  A  great 
number  of  engines  have  run  from  five  to  seven  years  without 
any  decided  cylinder  cutting.  In  discussing  water  injection  in 
semi-Diesel  engines  the  statement  was  made  that  the  nascent 
oxygen  combined  with  the  iron,  forming  a  ferric  oxide,  and  that 
this  caused  cylinder  cutting.  It  must  be  borne  in  mind  that 
the  temperature  attained  in  the  semi-Diesel  is  much  higher  than 
in  the  low-pressure  engine  using  fuel  oil.  On  the  other  hand, 
where  kerosene  is  used,  the  combustion  is  in  the  form  of  a  rapid 
explosion,  and  the  temperature  does  run  much  higher  than 
when  using  fuel  oil.  So  it  is  probable  that  water  injection 
with  kerosene  does  cause  ferric  oxide  deposits.  However,  the 
chief  cause  of  this  cutting  is  the  lack  of  proper  lubrication  of 
the  piston  and  cylinder.  It  is  a  common  occurrence  to  discover 
an  operator  using  a  light  gas-engine  or  automobile  oil,  and  these 
oils  do  not  have  sufficient  body  to  lubricate  an  oil  engine 
properly.  Regardless  of  statements  that  the  temperature  of 
the  cylinder  does  not  exceed  250°  Fahrenheit,  an  engineer  knows 
that  the  temperature  of  the  flame  in  the  cylinder  runs  up  into 
the  three  thousand  degrees  Fahrenheit,  and  that  this  heat  will 
burn  a  light  body,  low-fire  test  oil.  A  successful  cylinder 
lubricant  must  have  enough  body  to  stay  on  the  walls,  a  fairly 
high  fire  test,  and  must  burn  without  leaving  any  deposit  of  ash 
or  carbon.  Many  engineers,  especially  in  small  plants,  use  oils 
that  have  not  been  filtered  properly ;  these  oils  will  always  leave 
a  deposit  of  carbon. 

Many  instances  of  scored  cylinders  can  be  attributed  to  the 
faulty  design  of  cylinder  and  piston.  The  temperature  of  the 


LOW-PRESSURE  ENGINE  CYLINDERS  329 

exhaust  gases  is  high,  and,  as  they  pass  through  the  exhaust 
ports,  they  raise  the  temperature  of  the  exhaust  port  bridges  to 
at  least  800°.  There  is,  at  best,  but  a  poor  cooling  effect 
around  the  ports,  and  often  this  high  temperature  causes  the 
bridges  to  elongate.  Since  the  ends  of  the  bridges  are  held  from 
movement  by  the  rest  of  the  cylinder  casting,  the  bridge  must 
bend  and  warp  to  accommodate  this  growth  of  the  iron.  This 
will,  of  course,  score  the  piston  on  the  underside.  The  rough 
piston  then  continues  the  damage  by  cutting  the  cylinder  surface. 
When  the  cylinder  and  piston  are  inspected,  and  the  piston  has  a 
bright  streak  on  the  bottom,  it  is  safe  to  assume  that  the  bridges 
have  warped.  This  distortion  must  be  corrected  by  bringing 
the  bridge  back  to  its  original  position.  To  smooth  up  the 
bridge,  a  file  should  have  its  end  ground  square  with  the  edges 
sharp.  This  scraper  can  then  be  used  to  remove  the  excess 
metal.  If  the  damage  be  severe,  a  roughing  cut  can  be  made  with 
a  flat  file  or  a  block  of  emery  stone. 

In  some  engines  the  piston  is  made  very  light;  the  walls  and 
head  are  not  able  to  resist  the  high  pressures.  The  piston  walls 
tend  to  bend  into  an  elliptical  shape.  Once  the  piston  gets  out  of 
true,  it  is  only  a  question  of  time  until  the  cylinder  is  badly 
scored.  The  only  remedy  in  this  event  is  the  purchase  of  a  piston 
with  heavier  walls  and  top. 

There  exists  on  some  cylinders,  especially  those  on  vertical 
engines,  a  grooving  or  cutting  of  the  wall  surface  into  ridges  and 
valleys,  these  ridges  extending  about  the  girth  of  the  cylinder. 
Just  what  causes  this  manner  of  cutting  is  unknown,  though  it 
occurs  more  often  where  the  piston  has  considerable  play. 
Smoothing  with  a  scraper  provides  the  only  relief,  which  unfor- 
tunately is  but  temporary,  as  secondary  grooves  soon  begin  to 
appear  between  the  old  cuts. 

Fractured  Cylinders. — Fractured  cylinders,  'due  to  a  poor 
cooling  effect  of  the  circulating  water,  is  often  encountered.  It 
might  be  stated  as  an  axiom  that  a  fractured  cylinder  is  indicative 
of  a  lack  of  attention  on  the  part  of  the  engineer.  The  jackets 
of  practically  all  engines  provide  enough  water  storage  space  to 
absorb  sufficient  heat  to  prevent  the  engine  from  fracturing  due 
to  heat  stresses.  The  great  trouble  that  must  be  overcome  is 
the  lack  of  that  careful  attention  that  the  engineer  should  give 
the  machinery  under  his  care.  It  is  absolutely  imperative  that 
the  flow  of  cooling  water  should  be  uninterrupted.  It  should 


330  OIL  ENGINES 

not  be  necessary  to  state  that  the  water  must  begin  to  flow  as 
soon  as  the  engine  starts  firing.  If  an  engineer  lets  the  entire 
jacket  run  dry  when  starting,  he  should  not  blame  the  manufac- 
turer if  a  fracture  develops  in  the  cylinder. 

When  the  water  is  bad,  carrying  much  sediment,  the  deposits, 
which  will  always  occur  on  the  cylinder  walls,  must  be  removed. 
It  is  far  better  to  remove  the  mineral  or  vegetable  matter  before 
the  water  enters  the  jacket.  Unfortunately  this  demands  an 
expensive  purification  system  which  is  out  of  question  in  the 
average  plant.  It  follows  that  the  jackets  must  be  cleaned 
periodically.  If  the  scale  is  bad,  an  acid  solution  will  allow  it 
to  be  washed  out.  Graphite,  pumped  into  the  circulating  water 
pipe  at  frequent  intervals,  will  cause  the  scale  to  break  loose 
from  the  iron  walls  and  prevent  new  scale  from  forming.  Care 
should  be  observed  in  using  graphite.  The  scale  will  drop  off 
the  hot  cylinder  walls,  allowing  water  to  strike  the  fresh  portion 
of  the  wall  while  it  is  at  a  very  high  temperature.  The  best 
plan  is  to  cut  the  scale  with  acid  and  use  the  graphite  to  prevent 
any  further  scaling.  Due  to  the  low  temprature  of  the  cooling 
water,  commercial  boiler  compounds  do  not  prove  successful  as  a 
scale  solvent.  4 

In  journeying  among  oil  engine  plants,  one  is  struck  by  the 
great  number  of  fractured  cylinders  laying  around.  It  would 
appear  that  practically  no  effort  is  ever  made  to  repair  a  cylinder 
where  a  crack  extends  through  the  wall  to  the  interior.  Oil 
engine  cylinders  are  always  high  priced  (in  fact,  entirely  out  of 
proportion  to  the  factory  cost)  and  more  study  should  be  spent 
on  the  question  of  welding  the  fracture.  On  engines  of  less 
than  10-inch  diameter,  the  expense  of  welding,  with  the  risk  of 
it  being  unsatisfactory,  is  too  high  for  such  a  procedure  to  be 
recommended.  On  the  larger  cylinders,  if  the  services  of  an  ex- 
perienced oxyacetylene  welder  can  be  secured,  the  saving  is  well 
worth  the  trouble  of  welding.  In  welding  ordinary  cast-iron 
parts,  the  usual  method  is  to  cut  out  a  V  of  the  metal,  this  cut 
extending  through  the  entire  fracture.  This  allows  the  welding 
iron  or  steel  to  be  deposited  in  layers,  building  up  from  [the 
bottom  of  the  fracture.  If  this  is  done  in  a  cylinder,  there  is  a 
strong  tendency  for  the  cylinder  to  warp  out  of  shape.  A  small 
V,  to  open  up  the  top  of  the  fracture,  should  be  cut,  and  the 
welding  iron  should  be  kept  almost  to  the  burning  point  to  allow 
it,  when  deposited,  to  flow  as  deep  as  possible  into  the  fracture. 


LOW-PRESSURE  ENGINE  CYLINDERS  331 

The  blow-pipe  should  not  be  played  over  the  cylinder  walls  around 
the  fracture  any  more  than  sufficient  to  bring  the  edges  up  to  a 
welding  heat.  The  welding  material  should  not  be  piled  up 
above  the  surface  as  is  the  usual  practice.  After  cooling,  the 
weld  should  be  smoothed  down  with  a  file  and  scraper.  It  is 
best  to  use  soft  steel  rod  for  the  welding  material. 

This  method  has  been  used  in  a  few  cases  and  was  satisfactory 
in  a  low-pressure  engine.  It  would  not  be  a  success  in  Diesel 
engines  as  the  weld  usually  makes  either  a  low  or  high  spot  on  the 
cylinder  wall,  which  would  not  hold  a  very  high  compression, 
while  it  would  hold  quite  well  with  the  low-pressure  engine. 

In  the  case  of  cylinders,  the  two  important  items  that  demand 
attention  are  the  condition  of  the  water  jacket  and  the  lubrication 
of  the  cylinder  walls.  If  the  jacket  be  maintained  free  from  scale, 
and  the  cylinder  be  lubricated  to  the  correct  amount,  the  cylinder 
will  take  care  of  itself. 

Cylinder  Head  Packing. — Even  though  it  is  a  seeming  paradox, 
it  is  true  that  the  best  cylinder  packing  is  no  packing  at  all.  It 
seems  to  be  the  idea  of  the  average  engineer  that  he  must  use  a 
thick  packing  in  order  to  seal  the  joint  securely.  Even  though  it 
may  be  demonstrated  that,  theoretically,  the  more  compressible 
the  packing  is  the  greater  the  elongation  of  the  studs  before 
"  bio  wing"  will  occur,  in  actual  practice  a  thick  resilient  packing 
should  be  avoided.  In  designs  where  the  head  and  cylinder 
flanges  are  faced  straight  across,  the  best  possible  packing  is  a 
thin  sheet  of  copper.  This  sheet  should  be  annealed  and  made 
perfectly  smooth  and  straight.  The  flange  surfaces  should  be 
cleaned  and,  if  necessary,  smoothed  up  with  emery  cloth.  The 
copper  gasket,  which  should  also  encircle  the  studs  to  keep  it  in 
place,  will  maintain  a  tight  seal.  A  slight  blowing  on  starting  is 
not  harmful  on  a  copper  gasket  and  serves  to  relieve  any  excessive 
cylinder  pressure.  Some  engines  have  this  joint  grooved  for  a 
copper  ring  gasket.  In  replacements  the  copper  wire  should  be 
cut,  and  the  ends  scarfed  and  soldered.  The  wire  should  also 
be  annealed  before  using  so  that  it  will  compress  easily.  The 
copper  wire  gasket,  undoubtedly,  makes  the  best  seal  that  can  be 
secured.  Some  of  the  better  grade  engines  use  a  ground  joint 
between  the  head  and  the  cylinder.  If  the  head  was  never  re- 
moved, this  kind  of  seal  is  most  superior.  Unfortunately,  it 
often  becomes  necessary  to  inspect  the  cylinder  or  remove  the 
piston.  It  is  almost  impossible  to  tighten  up  enough  to  reseal 


332  OIL  ENGINES 

this  ground  joint.  Small  particles,  almost  invisible  to  the  eye, 
will  prevent  a  perfect  contact.  In  replacing  this  type  of  head,  it 
is  a  good  procedure  to  insert  a  copper  sheet  gasket.  The  use  of 
vulcanized  rubber  or  asbestos  gaskets,  even  with  wire  insertion, 
is  poor  practice.  The  gasket  seldom  holds  against  the  pressure, 
and  the  blowing  of  the  joint  at  starting  will  cause  the  gasket  to 
tear  and  be  rendered  worthless. 

A  word  might  be  added  about  the  "blowing"  of  this  joint. 
While  it  serves  to  relieve  excessive  cylinder  pressure,  the  engineer 
should  recognize  it  as  an  indication  that  he  has  pumped  too  much 
fuel  into  the  combustion  chamber  on  starting.  He  should  give 
the  pump  fewer  initial  strokes  on  the  next  starting.  If  the 
engine  " blows,"  the  operator  should  retard  the  fuel  pump  stroke 
so  that  the  oil  injected  is  less.  On  starting  an  engine,  the  usual 
governor,  since  it  is  not  in  a  state  of  perfect  equilibrium,  will  give 
the  fuel  pump  its  greatest  possible  stroke,  even  more  than  full- 
load  stroke,  and  the  fuel  injected  exceeds  the  capacity  of  the 
engine.  The  pump  handle  should  always  be  used  to  hold  the 
pump  stroke  to  a  low  value,  until  the  engine  has  come  up  to 
speed. 


CHAPTER  XX 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS 

Types  of  Pistons. — While  the  majority  of  the  two-stroke-cycle 
engines  of  the  low-pressure  type  use  pistons  having  deflector  lips, 
similar  to  Fig.  259,  there  are  several  other  designs  coming  into 
vogue.  Quite  a  number  adopt  the  double  piston,  Fig.  260.  This 
piston,  as  shown,  has  part  of  the  head  cut  away  to  form  a  de- 
flector for  the  air;  and,  to  allow  the  exhaust  to  uncover  at  the 
proper  time,  a  similar  portion  is  removed  from  the  bottom  side 


O 


FIG.  259. — Low-pressure  engine  piston  with  deflector. 

of  the  piston.  This  simplifies  the  casting  of  the  piston,  but  it  is 
likely  to  prevent  free  exhaust  as  the  curve  will  set  up  eddy 
currents,  and  the  scavenging  will  not  be  perfect  by  any  means. 
Still  another  design  is  Fig.  261,  which  is  used  on  the  De  La  Vergne 
four-stroke-cycle  type  D.H.  engine.  The  conical  head  will  allow 
expansion  without  seizing.  Another  design  which  is  coming 


O 


FIG.  260. 

into  favor,  especially  for  vertical  engines,  is  the  one  adopted  by 
the  Muncie  Co.  and  outlined  in  Fig.  262.  This  has  a  straight 
face  head,  and,  if  the  air  ports  enter  the  cylinder  at  an  angle, 
the  elimination  of  the  deflection  lip  will  not  prove  objectionable. 
In  those  engine  designs  where  the  scavenging  air  is  compressed 
in  the  front  end  of  the  cylinder,  the  common  practice  is  to  use 
a  crosshead  and  piston  rod.  This  .necessitates  a  considerable 
departure  in  the  piston  design.  Figure  275,  showing  the  Buckeye 

333 


334 


OIL  ENGINES 


Machine  Co.'s  design,  is  along  the  lines  of  this  type  piston  as 
ordinarily  built.  This  piston,  as  regards  strength,  is  of  excellent 
design.  The  head  is  strongly  ribbed — which  prevents  distortion 
of  both  the  head  and  piston  body.  See,  also,  Fig.  255. 

Piston  Clearance. — There  is  much  difference  in  the  practice 
of  engine  builders  in  regard  to  the  clearance  between  cylinder 
walls  and  piston.  On  new  engines  it  seems  to  range  anywhere 
from[j;32rinch  to  .005  or  .006  inch.  The  variation  is  not  dependent 
upon  size;  the  largest  clearance  encountered  has  been  on  pistons 
below  10  inches  in  diameter.  Apparently  the  values  chosen  have 


FIG.  261. — De  La  Vergue  piston  and  rod. 

.-*=-- r-aygio* 

depended  upon  the  builder's  viewpoint.  If  he  desired  absolute 
freedom  from  piston  seizing,  he  chose  a  large  value;  if  good  com- 
pression was  attractive,  a  small  clearance  was  used  at  the  risk 
of  piston  seizing.  In  operation,  the  engineer  should  see  that 
the  clearance  does  not  exceed  .008  inch;  that  is,  the  difference  in 
cylinder  and  piston  diameter  should  not  exceed  .0016  inch,  nor  be 
less  than  .005  inch.  This  clearance  value  is  considerably  greater 


FIG.  262. — Low-pressure  engine  piston  without  deflector. 

than  in  either  the  gasolene  or  Diesel  engine.  However,  owing 
to  the  heat  conditions  in  the  cylinder  of  the  two-stroke- 
cycle  type  of  engine,  the  piston  expansion  is  rather  extensive. 
Operating  at  a  fairly  high  rate  of  speed,  the  cooling  of  the  piston 
is  difficult,  especially  in  view  of  the  fact  that  either  the  frame  or 
the  front  end  of  the  cylinder  is  enclosed,  preventing  any  cooling 
by  air  currents  which  assist  materially  in  the  gasolene  engine. 
Since  the  two-stroke-cycle  receives  twice  as  many  fuel  charges 
as  does  the  gasolene  or  Diesel  for  the  same  number  of  revolutions 
per  minute,  the  amount  of  heat  that  the  cylinder  jacket  absorbs 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS   335 

is  approximately  twice  as  great.  The  piston  receives  more  heat 
than  it  can  radiate  at  ordinary  temperatures.  The  result  is 
that  it  must  reach  a  higher  temperature  limit  before  the  heat 
balance  is  attained.  Being  at  a  higher  temperature,  it  is  natural 
to  expect  the  piston  to  expand  more  than  does  a  gasolene  engine 
piston.  There  must  be  more  clearance  to  accommodate  this 
expansion.  While  there  must  be  clearance  ample  for  this,  the 
maximum  allowable  clearance  is  limited  as  welL  It  seems  to 
be  the  impression  of  most  engineers  that,  as  long  as  the  rings 
fit  snugly  and  hold  compression,  the  actual  piston  clearance  does 
not  matter.  On  the  contrary,  it  is  highly  important  that  there 
be  no  excessive  play.  The  air  ports  and  exhaust  passages  are 
practically  in  line.  If  the  piston  is  loose  in  the  cylinder,  the 
air  charge  will  flow  around  the  piston  into  the  exhaust  ports, 
even  though  the  rings  are  snug  enough  to  prevent  the  cylinder 
compression  from  being  lost.  A  great  many  instances  of  poor 
scavenging  are  traceable  to  excessive  piston  clearance.  Another 
common  practice  is  the  dependence  engineers  place  on  the  piston 
rings.  These  should  not  be  expected  to  hold  the  cylinder  com- 
pression with  the  piston  badly  worn.  Probably  nine  out  of  ten 
operators,  as  soon  as  the  piston .  shows  signs  of  wear,  order  a 
new  set  of  rings  and  feel  that  these  are  a  cure-all.  When  the 
piston  wear  exceeds  the  above-mentioned  clearances,  and  the 
engine  shows  signs  of  loss  of  power  or  excessive  fuel  consumption, 
it  becomes  necessary  to  install  a  new  piston  and  rebore  the  cyl- 
inder. Most  builders  furnish  replacement  pistons  from  \%  to 
Jf6  inch  oversize. 

Turning  a  New  Piston. — Viewed  from  all  aspects,  it  is  advisable 
to  purchase  the  new  piston  from  the  engine  builder.  Frequently, 
due  to  high  repair  prices  or  delay  in  delivery,  it  becomes  ad- 
vantageous to  have  the  piston  cast  at  a  local  foundry.  The  old 
piston  can  be  used  for  the  pattern.  A  core  box  can  be  cheaply 
made  since  the  piston  bosses  and  ribs  can  be  cut  in  the  core  itself. 
The  success  of  the  entire  process  depends  on  getting  the  core 
central  in  the  mold,  having  the  risers  of  considerable  height,  and 
in  using  iron  that  has  but  a  small  amount  of  scrap,  using  no 
stove  or  agricultural  scrap  at  all. 

In  many  instances  the  cylinder  is  not  scored  nor  worn  out  of 
round,  and  so  it  does  not  demand  reboring.  If  the  piston  be 
purchased  oversize  from  the  manufacturer  or  be  cast  at  the  local 
foundry,  it  is  necessary  for  the  engineer  to  have  the  piston  turned 


336  OIL  ENGINES 

to  the  correct  size.  It  is  usually  best  to  have  this  job  completed 
at  a  machine  shop.  In  those  installations  where  the  engineer  is 
expected  to  do  his  own  machine  work,  this  undertaking  need  not 
be  dreaded.  The  main  thing  is  to  exercise  great  care  in  centering 
it  in  the  lathe.  The  best  method  is  to  first  place  the  piston  on 
the  lathe,  chucking  the  head.  A  light  cut  should  be  taken  off 
the  inside  of  the  bottom  end,  as  well  as  on  the  edge,  to  square  up 
this  end  of  the  piston,  using  the  steady  rest  to  support  the  weight 
of  the  piston.  The  next  process  is  to  reverse  the  piston,  chucking 
from  the  inside  surface  that  has  just  been  finished.  Still  using 
the  steady  rest,  the  head  of  the  piston  is  finished  up.  A  drill  is 
inserted  in  the  tail  stock,  and  the  center  is  counter-bored  to 
receive  the  center  of  the  tail  stock.  The  steady  rest  is  then  re- 
moved, and  the  piston  tested  for  trueness.  If  it  is  a  little  out, 
this  should  be  corrected.  A  roughing  cut  is  next  taken  over  the 
body  of  the  piston,  ending  with  a  finishing  cut.  If  the  piston- 
pin  bosses  must  be  bored,  the  best  procedure,  on  an  ordinary 
lathe,  is  to  block  the  piston  up  on  the  carriage  and  bolt  the  boring 
tool  to  the  lathe  face-plate.  A  very  light  cut  should  be  first 
taken,  to  check  the  lining  up  of  the  piston.  If  it  is  not  blocked 
up  true,  this  reveals  the  error.  The  ring  grooves  can  be  made 
while  the  piston  is  chucked  on  the  lathe. 

After  taking  the  finishing  cut  on  the  piston,  a  file  should  be 
used  to  give  the  surface  a  good  finish;  the  use  of  emery  cloth  to 
follow  up  the  work  of  the  file  is  also  a  good  plan.  It  is  the 
practice  of  most  builders  to  give  a  slight  taper  to  the  piston 
from  the  first  ring  to  the  edge  of  the  head.  In  turning  a  new 
piston,  the  engineer  should  taper  it  at  this  point,  making  the 
variation  in  diameter  about  J^2  inch. 

Distorted  Pistons. — One  encounters  a  great  many  instances 
where  the  cylinder  is  badly  scored  and  where  the  operator  can- 
not account  for  this  damage,  he  being  insistent  that  the  piston 
has  been  supplied  with  plenty  of  lubrication.  Usually  investi- 
gation reveals  that  the  piston  walls  are  not  strengthened  by 
supporting  ribs,  and  the  piston  pin  is  locked  at  both  bosses  by 
set-screws  or  similar  devices.  If  the  piston  pin  becomes  heated, 
it  will  tend  to  lengthen.  When  there  are  no  ribs  to  resist  this 
force  and  the  pin  is  held  at  both  ends,  the  thin  piston  walls 
assume  an  elliptical  shape.  This  always  results  in  the  cylinder 
cutting  along  the  sides  in  line  with  the  pin  bosses.  If  the  engineer 
finds  that  the  piston  is  built  on  similar  lines,  it  is  well  to  file  a 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS   337 


FIG.  263. 


flat  surface  on  the  piston  around  the  bosses.  Then,  in  case  of 
elongation,  this  clearance  will  allow  the  piston  to  change  its 
shape  without  damage  to  the  cylinder. 

Where  the  damage  already  exists,  it  is  not  always  necessary 
to  rebore  the  cylinder,  even  though  the  scoring  be  deep.  If  the 
scoring  or  cutting  is  limited  in  area  and  does  not  extend  along 
the  entire  stroke,  the  damage  can  be  remedied  by  using  an  emery 
stone,  file  and  scraper.  In  such  instances  good  results  are  ob- 
tained by  first  using  an  emery  wheel  held  in  the  hand.  By 
rubbing  the  scored  spots  in  this  way  the  rough  ridges  are  re- 
moved, and  a  file  and  emery  stone,  finishing  up  with  the  scraper, 
will  smooth  the  work.  This 
process  has  been  used  on  many  strips 
occasions  where  the  cylinder  Iron 
looked  hopeless. 

Piston  Rings. — In  cases  of 
worn  piston  rings,  the  best  plan 
is  to  replace  them  since  their 
continued  use  means  loss  of 
power.  There  is  a  prevailing 
habit  of  engineers  to  let  the 

rings  stay  in,  no  matter  how  badly  worn,  if  the  engine  con- 
tinues to  pull  its  load.  Usually  the  engine  is  underloaded,  and 
its  ability  to  take  care  of  the  plant's  demand  is  no  criterion 
as  to  the  suitability  of  the  piston  rings.  In  most  plants  the 
best  way  to  decide  the  problem  of  ring  renewal  is  to  depend  on 
the  fuel  consumption.  If  this  shows  an  increase,  and  the 
rings  are  worn,  then  it  is  time  to  replace  them. 

Frequently,  these  new  rings  must  be  made  at  a  local  shop.  In 
such  cases  it  is  good  practice  to  have  the  rings  rough-turned  to 
an  outside  diameter  about  >{6  inch  larger  than  the  cylinder.  The 
ring  should  then  be  cut  and,  after  being  clamped  to  the  desired 
diameter,  finished  inside  and  out.  This  method  insures  a  ring 
that  will  hug  the  cylinder  walls  at  all  times.  Moreover,  the 
ring  should  be  made  almost  as  wide  as  the  groove;  the  difference 
should  not  exceed  .01  inch.  The  ring  should  equal  in  thick- 
ness the  depth  of  the  groove  less  .02  inch.  If  made  thinner,  the 
clearance  will  simply  fill  up  with  coked  oil. 

In  removing  piston  rings,  the  best  method  is  to  start  on  the 
one  nearest  the  piston  end  and  remove  each  one  successively. 
The  easiest  way  is  to  use  a  file  to  spring  one  end  of  the  ring  so 

22 


338 


OIL  ENGINES 


that  an  iron  strip, .such  as  a  barrel  hoop,  can  be  inserted  between 
ring  and  piston.  The  strip  is  worked  around  the  piston,  others 
being  added  as  the  process  continues.  The  ring  is  now  raised 
above  the  piston  surface  by  the  four  strips,  similar  to  Fig.  263. 
It  is  now  easy  to  slip  it  off.  The  strips  also  prevent  the  ring 
from  dropping  into  a  groove  as  it  is  slipped  off.  In  replacing 
rings,  the  same  method  can  be  followed. 

Distorted  Exhaust  Bridges. — Another  common  cause  of  a 
worn  piston  is  the  distortion  of  the  exhaust  port  bridges.  The 
cylinder  should  be  inspected  at  least  every  sixty  days,  and  if  the 
port  bridges  seem  bright  the  piston  will  probably  be  found  to 
be  cut  to  some  extent.  The  remedy  is  to  file  and  scrape  these 
bright  spots  until  the  piston  clears  them.  At  these  inspections 
the  piston  should  be  pulled  and  the  rings  examined.  If  badly 

gummed,  kerosene  will  usually 
loosen  them.  If  this  is  not 
successful,  placing  the  piston 
in  strong  lye  will  free  the 
rings. 

Fractured  Piston  Heads. 
— The  expansion  of  the  piston 
head  often  causes  minute  fire 
cracks  to  appear;  this  occurs 
but  seldom  in  conical  head 
pistons.  Frequently,  one  of 
these  fire  cracks  will  develop 
into  a  well-defined  fracture 
several  inches  in  length. 
Usually  this  extends  entirely 
FIG.  264.  through  the  head  and  allows 

the    gases  to   blow  through, 
and    decreased    power.     The 
engineer  is     to   replace  the 


Cap  Screws 
2?"C+oC. 


Iron  Cement-.. 


resulting 
tendency 


in    poor    compression 

of  the  inexperienced 
piston  at  a  heavy  cost.  This  replacement  is  entirely 
unnecessary  in  the  majority  of  cases.  If  the  piston  is  12  inches 
or  over  in  diameter,  the  method  described  in  Chapter  VI 
is  the  most  acceptable.  In  small  engines  this  entails  too  much 
time  and  skill.  A  cheaper  repair  is  shown  in  Fig.  264.  Here 
a  steel  plate  Y±  mcn  thick  is  fastened  over  the  crack  by  means 
of  a  series  of  machine  screws.  Iron  cement,  such  as  smooth-on, 
should  be  coated  over  the  piston  face  before  the  plate  is  drawn 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS  339 

into  place.  This  patch  will  hold  the  compression  and  will 
strengthen  the  head.  To  prevent  the  crack  from  developing  in 
length,  a  J^-inch  hole  should  be  drilled  in  the  head  at  the  ends  of 
the  crack.  The  machine  screw  heads  should  be  sawed  off  short 
so  that  they  do  not  project  into  the  cylinder  space  any  great 
amount;  if  they  do,  they  might  cause  preignition. 

Piston  Pins. — The  usual  type  of  piston  pin  consists  of  a  straight 
cylindrical  piece  of  steel,  hardened  and  ground.  In  most  designs 
it  is  held  in  both  bosses  by  means  of  two  set-screws,  the  pin  being 
countersunk  to  receive  the  conical  ends  of  the  set -screws.  In  some 
engines  the  pin  is  prevented  from  turning  by  the  use  of  a  key.  The 
use  of  a  set-screw  in  each  boss  constrains  the  pin  from  having 
any  opportunity  to  expand  lengthwise  without  distorting  the 
piston.  As  a  safeguard,  the  engineer  need  have  no  hesitancy 
about  removing  one  of  these  set-screws.  He  can  then  be  a  little 
more  at  ease  as  to  the  danger  of  the  piston  getting  out  of  round. 
Due  to  the  frequent  preignition  in  the  cylinder,  the  piston  pin  is 
subjected  to  extreme  hammer  blows.  If  it  is  not  properly  heat- 
treated,  a  flat  place  will  develop  where  it  comes  in  contact  with 
the  bronze  bearing.  Where  the  wear  becomes  considerable,  the 
pin  should  be  rotated  either  a  quarter  or  half  turn,  thereby  pre- 
senting a  true  surface  to  the  bearing.  When  the  pin  has  been 
so  rotated,  and  flat  places  have  been  worn  on  all  four  sides,  a 
new  pin  is  necessary.  On  engines  above  30  or  40  h.p.  it  is 
inadvisable  to  turn  the  pin  since  turning  it  results  in  con- 
siderable play  in  the  brasses.  Where  the  pins  are  not  a  snug  fit 
in  the  bosses,  the  latter  tends  to  pound  out  of  shape.  In  renewing 
pins,  the  bosses  should  be  examined  for  wear.  If  the  bosses  are 
out  of  round,  the  cavities  must  be  rebored,  and  the  new  pin  must 
be  made  large  enough  to  fit  the  new  bore.  Since  the  increase  in 
diameter  will  be  slight,  the  pin  need  not  be  reduced  in  diameter  at 
the  brasses.  These  can  be  enlarged  to  accommodate  the  new  pin. 
Piston  pins  should,  if  at  all  possible,  be  procured  from  the  builder. 
He  is  in  a  position  to  furnish  a  pin  heat-treated  and  ground. 
When  this  is  impossible,  a  pin  can  be  made  up  from  cold-rolled 
shafting.  If  facilities  are  at  hand,  it  should  be  case-hardened 
and  ground.  Where  the  engineer  is  satisfied  with  a  less  expensive 
method,  a  lathe-turned  pin,  smoothed  up  with  emery  and  with 
the  two  ends  ground  into  bearing  at  the  bosses,  will  suffice  for  a 
long  time,  though  its  wear  will  be  much  more_than  that^of  a 
hardened  pin. 


340 


OIL  ENGINES 


Connecting-rods. — Figures  265  to  269  show  the  types  of  con- 
necting-rods generally  used  on  the  low-pressure  engine.  Figure 
265,  Bessemer  Oil  Engine,  has  a  marine-type  crank  end  and  a  round 


FIG.  265. 


non-adjustable  piston  pin  end.  As  the  latter  has  no  means  of  tak- 
ing up  wear,  the  engineer  should  not  allow  this  solid  end  bearing 
to  become  too  worn;  prompt  replacement  by  a  new  bushing  will 


FIG.  266. — Buckeye-Barrett  connecting  rod. 

help  maintain  a  smooth-running  engine.  Figure  266,  Buckeye 
Oil  Engine,  shows  a  rod  along  somewhat  similar  lines.  The 
principal  difference  is  in  the  split  wrist-pin  bearing.  In  taking  up 


FIG.  267. — Primm  connecting"rod.^ 

the  wear,  this  split  bearing  will  not  maintain  a  perfect  bore.  It 
will  tend  to  go  out  of  round.  When  making  adj  ustment,  the  brass 
should  be  slipped  over  the  pin,  which  is  removed  from  the  engine 


illllllllliii 


FIG.  268. — Muncie  connecting  rod. 

and  coated  with  Prussian  blue.  Rotating  the  bushing  reveals 
where  it  bears  hard  on  the  pin.  The  operator  can  bring  the 
bushing  true  by  judicious  scraping.  Too  many  engineers  feel 


PISTONS,  PIS  TON  PINS  AND  CONNECTING-RODS     341 

that  such  attention  to  details  is  unnecessary;  nevertheless,  the 
life  of  any  engine  can  be  doubled  by  the  exercise  of  due  vigilance 
by  the  operator.  Figure  267,  Primm  Oil  Engine,  shows  a  rod 
having  a  wedge  adjustment  at  both  ends.  Figure  268,  Muncie 
Oil  Engine,  shows  a  rod  used  on  some  engines  with  both  ends  of 
the  marine  type.  Figure  261,  De  La  Vergne  D.H.  Engine, 
shows  a  rod  that  closely  follows  Diesel  practice,  with  the  addi- 
tional feature  of  oiling  the  piston  pin  by  a  passage  in  the  rod 
itself. 

The    connecting-rod    used   in  the  Fairbanks-Morse   Vertical 
Engine  is  shown  in  Fig.  269.     The  crank  bearing  has  a  renewable 


FIG.  269. — Fairbanks- Morse  vertical  engine  connecting  rod. 

liner,  and  any  slight  wear  can  be  taken  up  by  removal  of  a  shim. 
The  piston-pin  bearing  is  a  bronze  bushing,  split  on  one  side. 
This  bushing  fits  into  the  rod  and  is  held  by  the  adjusting,  or 
take-up,  block  set-screw.  When  the  bearing  has  worn,  it  is 
necessary  to  remove  the  rod  and  piston  pin  from  the  piston. 
The  brass  shim  or  strip,  which  fills  the  space  between  the  two 
edges  of  the  bushing,  is  taken  out  and  filed  until  the  bushing  will 
fit  the  pin.  This  must  be  done  gradually  in  order  not  to  reduce 
the  shim  too  much.  The  bushing  and  shim  are  placed  in  the 
rod  and  the  pin  inserted;  the  take-up  block  is  then  forced  down 
to  a  solid  contact  by  the  screw.  Nothing  should  be  taken  for 
granted.  The  pin  should  be  rotated,  being  coated  with  Prussian 
blue,  and  any  high  spots  in  the  bushing  scraped  away.  The 
engineer  must  remember  that  the  bushing  must  come  into  con- 
tact with  the  shim.  If  the  high  spots  are  not  scraped,  the  bushing 
will  not  bear  true  since  its  design  is  such  that  it  becomes  elliptical 
when  adjusted. 

Adjustments. — In  operation,  the  engine  should  never  be 
allowed  to  run  with  any  play  in  the  brasses.  Wear  is  easily 
detected  by  the  thumping  sound  as  the  piston  reverses  at  the 
end  of  the  explosion  stroke.  At  the  moment  of  explosion  the 


342  OIL  ENGINES 

impetus  given  the  crank  and  flywheel  is  sufficient  to  cause  it  to 
run  ahead  of  the  piston  toward  the  end  of  the  stroke.  The 
pin,  then,  might  be  said  to  be  out  of  contact  with  the  pressure 
side  of  the  brass.  Upon  reversal  of  the  crank,  the  connecting- 
rod  brass  comes  into  contact  with  the  piston  pin,  producing  a 
blow  or  thump.  If  the  brasses  are  snug,  the  pin  is  never  out  of 
contact.  If  the  wrist  end  has  a  wedge  adjustment,  it  is  an  easy 
matter  to  take  up  the  lost  motion  without  pulling  the  piston. 
The  same  applies  to  the  crank  end,  regardless  of  the  particular 
type  of  bearing.  However,  if  the  wrist  end  be  a  marine-type 
or  screw-adjusting  box,  it  will  be  necessary  to  pull  the  piston  in 
order  to  make  the  proper  adjustment.  The  brass  should  be 
drawn  up  tight,  and  then  the  bolts  should  be  backed  off  a  sixth 
of  a  turn.  Some  engineers  attempt  to  adjust  without  using 
shims  between  the  two  halves  of  the  brass.  It  is  advisable  to 
insert  shims  so  that  the  pressure  of  the  bolts  is  on  the  shims  and 
not  on  the  pin  itself.  In  tightening  the  brass,  the  pin  is  with- 
drawn from  the  piston.  When  the  correct  fit  is  secured,  the  pin 
is  driven  out  of  the  rod,  and  the  piston,  connecting-rod  and  pin 
are  reassembled.  No  connecting  rod  will  run  without  heating  if 
there  is  no  provision  made  for  a  small  amount  of  clearance  be- 
tween pin  and  brass.  The  fit  should  be  snug,  yet  not  tight.  A 
good  way  to  determine  whether  the  adjustment  is  correct  is  to 
"jump"  the  piston.  If  a  5-foot  pinch  bar  will  just  cause 
the  piston  to  move,  it  is  safe  to  assume  that  the  brasses  are  snug 
enough. 

Connecting-rod  Brasses. — The  piston-pin  bearing,  or  box,  is 
usually  made  of  phosphor  bronze — a  babbitt  bearing  will  not 
stand  up  very  well  on  account  of  the  heat  conditions  within  the 
piston.  If  is  well  to  remember  that  it  is  not  necessary  to  have 
the  bearing  completely  surround  the  pin.  The  pressure  actually 
falls  on  a  very  small  portion  of  the  bearing,  and  the  lubrication  is 
better  with  part  of  the  brass  cut  away,  as  shown  in  Fig.  270. 
Frequently,  the  engine  manufacturer  does  not  do  this,  and  the 
engineer  will  make  no  mistake  if  he  removes  the  surplus  portion 
before  using  the  bearing. 

The  crank-pin  bearing  used  on  this  type  of  engine  up  to 
35  h.p.  is  usually  a  split  babbitt  bushing  enclosed  in  the  bear- 
ing housing  or  box.  Ordinarily,  the  manufacturer  die-casts 
these  bearings  and  reams  or  broaches  them  to  exact  size.  If  the 
die-casting  is  not  so  finished,  the  surface  is  not  perfect,  and  the 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS   343 


metal  has  a  tendency  to  "drag."  With  the  die-cast  bearing, 
in  case  of  renewal  the  cheapest  way  is  to  buy  a  new  one  from  the 
engine  builder,  since  the  plants  using  these  small  engines  are 
not  equipped,  as  a  rule,  to  make  a  bushing.  In  case  of  urgency, 
where  it  is  impossible  to  wait  for  a  new  bushing  from  the  factory, 
it  is  easy  to  have  a  local  machine  shop  cast  a  babbitt  bushing, 
around  a  mandrel  placed  in  a  piece  of  pipe.  The  engineer  should 
see  that  the  machinist  who  fits  the  bushing  to  the  engine  pin  uses 
extreme  care  in  bringing  it  to  a  perfect  contact  with  the  pin. 


rr 


o 


FIG.  270. — Big-end  rod  bearing. 

On  larger  engines  the  removable  bushing  is  seldom  used.  The 
crank-pin  bearing  housing  is  usually  made  of  steel  or  cast  iron, 
though  a  few  housings  have  been  made  of  bronze;  the  cast-steel 
housing  is  by  far  the  best.  The  box  is  lined  with  babbitt,  and 
the  best  babbitt  is  always  the  cheapest  in  the  long  run. 

Quite  often  one  sees  a  crank  box  that  will  not  retain  the  babbitt. 
The  fault  generally  proves  to  be  a  lack  of  sufficient  anchorage  in 
the  bearing.  If  the  box  is  merely  drilled  in  a  number  of  places 
for  babbitt  anchors,  it  will  be  well  to  put  it  on  a  planer,  or  shaper, 
and  cut  dovetail  slots  in  the  surface  of  the  housing.  These 
slots  will  hold  the  babbitt  under  unusually  severe  conditions. 

Babbitting  a  Crank  Bearing. — In  rebabbitting  a  box,  it  is 
never  advisable  to  run  it  with  the  box  cold.  If  this  is  done,  the 
babbitt  will  seldom  unite  with  the  box.  Where  the  engine  is 
small,  as  good  a  method  as  any  is  to  secure  a  mandrel  the  same 
diameter  as  the  crank  pin  and,  after  placing  this  in  the  housing 
(which  has  been  heated),  run  the  bearing  around  the  mandrel. 
Any  bad  spots  in  the  babbitt  can  be  smoothed  up,  and  the  entire 


344 


OIL  ENGINES 


bearing  scraped  into  a  good  fit  to  the  pin.  On  large  engines  the 
same  method  as  is  used  on  a  Diesel  engine  should  be  followed. 
In  running  a  new  bearing,  a  liberal  amount  of  shims  should  be 
used  between  the  two  housing  halves  in  order  that  the  babbitt 
can  wear  considerable  and  still  leave  room  between  the  two  hous- 
ing parts  for  "  take-up."  Extreme  care  should  be  exercised  to  see 
that  the  babbitt  is  not  overheated  in  melting.  Regardless  of 
the  question  of  economy,  it  does  not  pay  to  use  the  old  scrap 
babbitt  in  the  ladle.  It  carries  too  much  abrasives;  it  is  best  re- 
served for  ordinary  work,  such  as  line-shaft  boxes. 

Crank-pin  Clearances. — The  clearance  for  the  crank  pin,  which 
should  not  exceed  .02  inch,  is  indicated  by  a  very  slight  "  jump." 
As  regards  the  value  of  side  play  between  the  big-end  bearing  and 
the  crank  web,  this  of  course  differs  in  various  make  engines. 
Some  demand  more  liberal  clearance  than  others  if  the  brass 
does  not  bind  after  warming  up.  '  A  fair  value  is  %4  inch,  or  just 
enough  to  be  detected  by  using  a  small  pinch  bar. 

When  an  engine  is  first  started  or  after  a  new  bearing  is  in- 
stalled, the  engine  should  be  run  without  load  for  a  couple  of 
hours.  If  a  bearing  runs  hot  in  service,  it  never  pays  to  shut 
down,  for  the  babbitt  will  surely  grip  the  pin.  The  load  should 
be  thrown  off  and  the  engine  run  at  a  slow  speed,  with  the  lubri- 
cation increased,  until  the  bearing  cools  off. 


Spring- 


FIG.  271. — Piston  pin  oiling.     (Fairbanks  Morse  Co.) 

Crank -pin  and  Piston-pin  Lubrication. — Probably  the  oiling  of 
the  wrist-pin  box  has  caused  more  trouble  and  worry  to  the  en- 
gineer than  the  oiling  of  all  the  rest  of  the  engine.  Some  builders 
depend  on  picking  up  enough  oil  from  the  cylinder  walls  to 


PISTONS,  PISTON  PINS  AND  CONNECTING-RODS     345 

lubricate  the  pin,  the  pin  being  drilled  lengthwise  and  provided 
with  a  scoop  at  one  end,  Fig.  271.  The  great  objection  to  such 
a  method  of  oiling  is  the  likelihood  of  the  scoop  picking  up  carbon 
particles  and  thereby  clogging  the  oil  passage,  causing  a  trouble- 
some pin.  A  second  arrangement  is  to  have  a  pipe  passing 


FIG.  272. — Mietz  and  Weiss  low-pressure  oil  engine,  showing  lubrication  system. 

through  the  cylinder  walls,  allowing  the  oil  issuing  from  the  end 
of  the  pipe  to  be  picked  up  by  a  groove  on  the  piston  and  then 
conveyed  to  the  pin,  Fig.  272.  Still  another  plan  is  to  supply  the 
pin  by  means  of  a  drilled  hole  extending  through  the  connecting- 
rod  from  the  crank  end,  Fig.  261.  Probably  the  best-  way  to 
oil  the  pin  of  a  horizontal  engine  is  to  use  a  device  such  as  a 


346 


OIL  ENGINES 


wick  or  wiper  oiler  in  connection  with  a  mechanical  oil  pump, 
Fig.  251. 

A  contrivance  that  has  been  used  on  an  inclosed-frame  engine 
is  outlined  in  Fig.  273.  A  IJ^-inch  brass  pipe  is  slotted  on  one 
side  and  the  ends  capped.  This  pipe  is  fastened  to  the  inner  wall 
of  the  piston  by  two  clamping  bands  and  extends  out  16  inches  be- 
yond the  end  of  the  piston.  A  J^-inch  connection  is  run  to  the  pin 
boss  connecting  with  the  oil  passage  already  in  the  pin.  The 
IJ^-inch  pipe  receives  the  oil  through  a  tube  running  from  the  oil 
pump,  which  is  mounted  on  the  engine  frame  back  of  the  cylinder. 


FIG.  273. — Piston  pin  oiler. 

Since  the  slot  is  as  long  as  the  engine  stroke,  the  oil  supply  to  the 
pin  is  positive.  The  inertia  of  the  oil  as  the  piston  moves  assists 
in  insuring  a  steady  oil  stream.  No  matter  what  system  be 
used,  it  must  be  given  attention.  The  piston  pin  is  in  a  high  tem- 
perature zone  and  needs  a  constant  oil  supply  to  keep  in  normal 
condition. 

The  usual  way  of  oiling  the  crank  pin  is  by  a  centrifugal  oil 
ring,  Fig.  272,  which  is  by  far  the  simplest  and  most  reliable  de- 
vice. Only  one  precaution  need  be  exercised.  The  big-end  bear- 
ing should  have  liberal  oil  grooves  cut  in  the  babbitt  in  order  to 
distribute  the  oil  as  it  emerges  from  the  drilled  passage  in  the 
pin.  Whenever  the  bearing  gets  warm,  the  babbitt  may  be 
forced  into  the  oil  passage,  closing  it.  The  oil  passage,  then, 
should  always  be  cleaned  out  after  the  hot  box  has  been  cooled. 


CHAPTER  XXI 
ENGINE  FRAMES.     BEARINGS.     SHAFTS.    FLYWHEELS. 

Engine  Frames. — In  the  matter  of  frame  design,  each  engine 
builder  has  followed  his  own  ideas.  Unlike  steam  engine  manu- 
facturers, hardly  any  two  low-pressure-engine  builders  use  the 
same  design  of  frame.  However,  all  may  be  separated  into  two 
types — the  open  frame,  where  the  scavenging  air  is  compressed 
in  the  front  end  of  the  cylinder;  and  the  inclosed  frame,  where  the 
air-tight  frame  itself  serves  as  the  air  compressor.  Figure  256  is 
a  view  of  an  open-frame  while  Fig.  251  is  a  cross-section  of  an 
inclosed-frame  engine.  While  both  show  a  horizontal  engine,  it  is 
in  the  vertical  type  engine  that  the  inclosed  frame  is  used  exclu- 
sively. This  is  for  the  reason  that  an  open  frame  with  cylinder 
air  compression  would  make  the  engine  much  higher  than  is 
desirable. 

Inclosed  Frame. — The  inclosed  frame  is  immensely  attractive 
both  from  a  manufacturing  and  an  operating  viewpoint.  Since 
all  parts  are  bound  together  the  frame  can  weigh  less  for  the  same 
strength.  Being  inclosed,  the  matter  of  keeping  the  bearings 
and  cylinder  free  from  grit  is  very  much  simplified.  However, 
of  late,  a  number  of  open-frame  engines  are  being  equipped  with 
dust-proof  steel  covers.  Many  engines  of  the  horizontal  two- 
stroke-cycle  type  have  frames  that  are  entirely  inclosed,  access 
to  the  interior  parts  being  had  only  by  a  small,  opening  at  the 
front  of  the  frame.  This  opening  is  taken  up  by  the  air-check 
valve,  and  inspection  of  the  parts  involves  removal  of  the  valve 
and  the  suction  piping.  In  an  engine  of  this  design  the  engineer 
should  not  fall  into  the  lamentable  habit  of  neglecting  to  inspect 
the  connecting-rod  brasses.  It  is  not  easy  to  do  this,  but  even 
though  it  does  involve  considerable  effort  the  air  valve  should 
be  removed  at  least  monthly,  and  the  crank  box  inspected  for 
wear.  There  is  a  tendency  at  all  times  for  this  bearing  to  wear 
unevenly,  allowing  the  rod  to  get  out  of  line,  and  it  is  more  likely 
to  happen  in  the  inclosed  engine  if  the  engineer  is  lax  in  his 
inspection. 

347 


348  OIL  ENGINES 

Another  detail  of  importance,  especially  in  the  horizontal  en- 
gine, is  the  necessity  of  keeping  the  crankcase  free  from  excess 
lubricating  oil.  In  many  plants  the  engineer  is  careless  in  this 
matter  and  allows  the  oil  to  accumulate  until  the  crank  strikes 
the  oil  surface.  This  causes  the  oil  to  splash  into  the  piston  and 
also  causes  the  air  to  be  charged  with  a  fog  of  lubricating  oil 
particles.  -  This  fog  of  lubricating  oil  is  blown  along  with  the 
air  into  the  cylinder  at  the  moment  the  air  port  is  opened.  These 
particles  blow  on  out  through  the  exhaust,  giving  it  a  decidedly 
smoky  appearance.  The  oil  which  splashes  into  the  piston  may 
strike  the  hot  piston  head,  carbonize  and  adhere  in  a  thick  coat 
or  scale.  Means  of  removing  the  heat  from  the  piston  head  are 
meager  at  the  best,  and  scale  is  a  poor  conductor  of  heat.  There- 
fore, this  splashing  oil  will  likely  contribute  to  a  fractured  piston 
head.  In  the  vertical  cylinder  this  carbonized  scale  on  the  in- 
terior of  the  piston  has  a  habit  of  dropping  down  on  the  crank- 
pin  and  piston-pin  brasses.  Small  particles  working  in  between 
the  pin  and  brass  cause  a  good  many  hot  boxes.  The  splashing 
lubricating  oil,  in  a  horizontal  engine,  strikes  the  cylinder  walls 
in  excessive  amounts.  This  oil  will  invariably  gum  up  the  piston 
rings  and  frequently  cut  the  piston.  Figure  272  is  a  cross-section 
of  the  Mietz  and  Weiss  engine  which  uses  the  inclosed  frame; 
the  Fairbanks-Morse  inclosed  frame  appears  in  Fig.  253. 

Engines  using  the  front  end  of  the  cylinder  as  the  air  com- 
pressor are  free  from  those  troubles  due  to  the  oil  in  the  crank- 
case.  The  crankcase,  in  such  designs,  is  entirely  separated  from 
the  air  chamber.  As  a  result  of  this  separation,  quite  a  number 
of  these  engines  use  a  splash-oiling  system  for  the  lubrication  of 
the  crank  pin  and  main  bearings.  This  gives  a  copious  supply 
of  oil  to  these  parts.  The  oil,  however,  should  be  removed  oc- 
casionally for  refiltering.  When  the  runs  are  long,  the  oil  should 
be  drawn  off  and  cool  oil  substituted.  It  does  not  require  many 
days  of  operation  to  raise  the  oil  temperature  up  to  a  point  where 
the  lubrication  of  the  pin  becomes  unsatisfactory.  Figure  255 
is  a  cross-section  of  the  Bessemer  engine,  which  uses  the  splash- 
oiling  system. 

Open  Frames. — Figure  274  illustrates  the  frame  of  the  De  La 
Vergne  four-stroke-cycle  low-pressure  engine.  Since  no  scaveng- 
ing air  is  used,  the  frame  does  not  embody  the  compressor 
feature.  This  frame  in  many  respects  follows  closely  the  design 
of  horizontal  Diesel  engines,  though  of  much  lighter  weight.  The 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  349 

cylinder  jacket  is  part  of  the  frame,  and  support  is  given  the 
cylinder  over  its  entire  length.  This  extensive  foundation  bear- 
ing surface  makes  this  frame  very  rigid. 


FIG.  274. — Cylinder  with  removable  liners  De  La  Vergne  D.H.  low  compression 

oil  engine. 

Figure  275,  Buckeye-Barrett  engine,  is  a  typical  design  of  the 
two-stroke-cycle  engine  using  cylinder  air-compression.  Since 
this  type  of  air  compression  necessitates  the  use  of  a  piston  rod, 


FIG.  275. — Buckeye-Barrett  oil  engine. 

a  crosshead  is  used.  The  adjustments  of  the  crosshead  are  iden- 
tical with  those  occurring  in  steam  engine  practice.  Since  most 
oil  engine  operators  are  familiar  only  with  the  trunk  piston  type 


350  OIL  ENGINES 

engine,  frequently  the  crosshead  is  ignored,  and  the  wear  on  the 
lower  shoe  is  not  taken  up  at  the  proper  time.  It  is  apparent 
that,  if  the  lower  crosshead  shoe  wears,  the  piston  rod  will  ride 
on  the  bottom  part  of  the  stuffing-box.  The  piston  is  usually 
about  40  per  cent,  as  long  as  the  piston  rod.  Then  if  the 
crosshead  shoe  wears  ^{Q  inch,  the  rod  will  rest  on  the 
stuffing-box,  the  piston  rod  fulcruming  at  this  point.  When 
the  fuel  charge  explodes,  the  piston,  in  forcing  the  crosshead  to 
the  front  end,  will  tend  to  tilt  an  amount  corresponding  to  the 
crosshead  shoe  wear.  Being  of  considerable  -  length,  cylinder 
scoring  may  be  caused  by  either  the  front  or  rear  end  of  the  piston. 
This  has  happened  in  a  number  of  instances  where  the  engineer 
was  careless  about  taking  up  crosshead  shoe  wear.  While  the 
lower  shoe  wears  more  rapidly,  due  to  the  higher  pressure  exerted 
on  the  piston  during  the  explosion  stroke,  there  is  some  wear  on 
the  top  shoe.  Unlike  the  steam  engine,  there  is  a  reversal  of 
direction  of  the  pressure  on  the  crosshead ;  during  the  compression 
stroke  the  flywheel  forces  the  piston  to  the  rear,  and  the  vertical 
component  of  this  pressure  on  the  crosshead  is  upward.  Since 
the  pressure  is  fairly  low,  the  wear  is  slight,  and  usually  no  ad- 
justing wedge  is  incorporated  in  the  design.  Even  though  this 
be  true,  it  is  advisable  for  the  engineer  to  examine  the  upper  shoe 
for  wear.  It  is  extremely  difficult,  after  the  engine  is  once  in 
operation,  for  the  engineer  to  detect  on  which  shoe  the  wear  has 
occurred.  The  one  correct  method  is  to  remove  the  piston  and 
run  the  center  line.  This  involves  too  much  time  and  labor  to 
be  done  often.  A  good  many  operators  depend  on  the  stuffing- 
box  to  serve  as  a  gage  in  adjusting  the  crosshead,  raising  the  lower 
shoe  until  the  piston  rod  apparently  centers  the  stuffing-box. 
The  objection  to  this  lies  in  the  wear  in  the  stuffing-box,  destroy- 
ing its  usefulness  as  an  indicator.  In  the  data  book,  covering 
dimensions  and  adjustments  of  the  engine,  which  every  engineer 
should  have  in  his  possession,  when  the  engine  is  first  installed, 
the  crosshead  measurements  should  be  entered.  Using  a  mi- 
crometer, the  distances  between  outside  surface  of  the  shoes  and 
the  inside  edges  of  the  crosshead  should  be  noted.  The  crosshead 
can  be  turned  enough  to  cause  the  shoes  to  be  horizontal  and 
clear  of  the  guides.  In  taking  up  any  wear,  the  wedges  should  be 
moved  to  bring  the  shoes  back  to  the  original  measurements. 
Where  the  upper  shoe  is  babbitted  directly  onto  the  crosshead, 
the  wear  can  only  be  taken  up  by  rebabbitting.  Consequently, 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  351 


it  is  necessary  to  allow  the  wear  to  go  awhile,  before  this  rebab- 
bitting  is  done.  Special  care  should  be  used  in  keeping  the  oil 
grooves  on  the  shoes  clean  of  grit. 

Another  detail  that  should  not  escape  the  engineer's  attention 
is  the  piston-rod  lock-nut.  This  lock-nut  serves  to  jamb  the 
rod  into  the  crosshead.  If  the  nut  works  loose,  the  rod  will  likely 
unscrew  a  thread  or  so.  This  will  raise  the  compression  in  the 
cylinder  by  reducing  the  clearance.  In  cases  where  the  rod  has 
worked  entirely  free  from  the  crosshead,  the  cylinder  head  has 
been  broken  by  the  piston  striking  it.  If  the  nut  is  jambed  up 
hard,  and  the  locking  set-screw 
or  cotter  key  properly  adjusted, 
there  should  be  but  little  danger. 
Nevertheless,  the  rod  should  be 
examined  each  time  the  crankcase 
door  is  opened. 


ROUND  RINGS 


FIG.  276. — Air  suction  valve,  F.  M.  &  Co. 
horizontal  oil  engine. 


GUIDE 

FIG.  277.— Air  valve,  F.  M.  &  Co. 
vertical  oil  engine. 


Air  Suction  Valves. — The  air  suction  valve  is  a  frequent  source 
of  trouble.  This  valve,  when  made  of  leather  and  after  being  in 
use  for  some  time,  will  have  a  tendency  to  cup  and  partly  pull 
through  the  valve  seat.  In  the  inclosed  frame,  when  the  crank- 
case  is  not  kept  drained  of  oil,  the  breathing  action  of  the  valve 
causes  the  leather  to  become  saturated  with  oil,  rapidly  destroy- 


352 


OIL  ENGINES 


ing  the  valve.  The  best  leather  to  use  in  replacing  the  worn 
valves  is  an  acid-  and  oil  proof  leather-belting  stock;  oak-tanned 
leather  will  not  stand  up  very  long.  Figure  276  illustrates  the 
leather  valve  used  on  the  Fairbanks-Morse  horizontal  engine, 
while  Fig.  277  is  the  valve  used  on  their  vertical  engine. 

In    many  engines  the  air    valve  is  noisy  in  action.     This, 
ordinarily,  is  due  to  its  having  too  great  a  lift.     The  remedy  is 


m                       I       -INI 

AIR  DUCT  i 

1 
| 

FIG.  278. — Mietz  and  Weiss  three  ported  oil  engine. 

to  cut  off  part  of  the  valve  guard,  thereby  reducing  the  valve 
lift.  In  those  engines  where  the  air  valve  is  a  brass  poppet  with 
a  rubber  ring  on  the  -valve  seat  and  a  spring  to  cause  the  valve  to 
seat  quickly,  the  noise  is  usually  not  great.  In  cases  where  it  is 
objectionable,  it  is  better  to  increase  the  thickness  of  the  rubber 
ring,  thus  decreasing  the  valve  lift,  rather  than  to  change  the 
spring  tension.  If  the  springs  are  weakened,  the  time  interval 
of  closing  is  increased,  thus  reducing  the  compression  efficiency 
by  allowing  the  air  column  to  reverse  and  flow  back  out  the  suc- 
tion. Muncie  Oil  Engine  Co.  makes  use  of  a  valve  of  this  design. 
Some  of  the  inclosed  engines  are  three-ported  instead  of  two- 
ported.  This  design  eliminates  the  air  suction  valve,  and  the 
piston,  by  uncovering  a  port,  allows  the  air  to  flow  into  the  crank- 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  353 


case.  The  one  objection  that  has  been  advanced  against  the 
three-ported  engine  is  the  lower  volumetric  efficiency  of  the  com- 
pressor. The  piston  must  move  a  considerable  distance  on  the 
return  stroke  before  the  suction  air  port  is  closed,  lowering 
the  volumetric  efficiency  by  the  percentage  of  the  total  stroke 
the  "piston  moves  before  covering  the  port.  Figure  278  is  a 
cross-section  of  the  Mietz  and  Weiss  engine  which  uses  the 
three-ported  design. 

It  is  well  to  remember  that  it  is  impossible  to  make  the  air 
suction  noiseless  as  long  as  there  is  no  muffler  on  the  air  suction 
line.  Some  engine  designs  include  a  muffling  effect  by  drawing 


FIG.  279. — Bessemer  Corliss  air  valve. 

the  air  through  the  hollow  engine  sub-base.  In  most  of  these 
cases  the  air  passes  across  the  top  of  the  foundation  and  below 
the  oil  pan.  There  is  a  tendency  in  such  a  construction  for  the 
current  of  air  to  pick  up  any  particles  of  cement  that  are  on  the 
surface  of  the  concrete  foundation.  To  safeguard  this,  on  erec- 
tion of  an  engine  a  couple  of  gallons  of  linseed  oil  should  be  poured 
on  the  foundation  surface  beneath  the  engine.  This  makes  a 
dust-proof  seal  that  will  eliminate  all  cement,  dust  or  grit. 

Some  engines  make  use  of  a  piston  air  valve,  while  others  have 
adopted  a  rotating  valve  of  the  so-called  " Corliss"  type.  These 
valves  usually  last  for  a  number  of  years  before  replacement. 
The  objectionable  feature  is  the  wear  on  the  valve  cage  or  cavity. 
When  the  valve  is  replaced,  it  is  imperative  that  the  valve  cavity 
be  rebored  if  it  is  not  of  the  renewable  type.  These  two  designs 
of  valves  require  lubrication,  or  they  cut  quickly.  They  elimi- 
nate all  breathing  noise,  and  this  is  an  attractive  feature  in  an 
engine  that  is  located  in  a  congested  district. 

23 


354  OIL  ENGINES 

Figure  255  shows  the  location  of  the  Corliss  air  valve  on  the  Bes- 
semer Oil  Engine  under  the  cylinder  casting;  the  valve  is  driven 
by  r.n  eccentric  from  the  crankshaft.  Figure  279  shows  the  details 
of  the  same  valve.  This  is  made  of  a  valve  bushing;  this  reduces 
replacement  cost  in  case  of  wear.  In  order  to  secure  the  proper 
amount  of  air  the  eccentric  must  not  be  allowed  to  slip.  In  one 
plant  the  engine  refused  to  run,  despite  the  effort  of  the  engineer 
and  an  engine  expert.  By  accident,  after  both  had  given  up  in 
disgust,  it  was  discovered  that  the  eccentric  had  shifted,  prevent- 
ing the  air  valve  from  opening  until  late  in  the  air  compression 
stroke.  Various  adjustments  of  the  timing  of  this  air  valve  have 
been  tried  out.  The  builders  recommend  that  the  valve  be  set 
to  open  when  the  crank  is  40  degrees  past  the  front,  or  outstroke, 
dead-center,  and  to  close  when  the  crank  is  30  degrees  past  rear, 
or  the  cylinder  head,  dead-center.  This  gives  ample  time  for  the 
complete  filling  of  the  air  .cavity.  There  is  no  reason  why  the 
valve  should  not  open  when  the  crank  is  30  degrees  instead  of  40 
degrees  past  dead-center.  The  column  of  air  rushing  into  the  cyl- 
inder has  sufficient  inertia  to  prevent  any  backward  flow  when 
the  suction  valve  is  opened  while  the  discharge  port  is  still  un- 
covered. This  will  allow  the  valve  to  close  earlier,  preventing 
air  loss  through  the  suction  valve.  This  will  increase  the  volu- 
metric efficiency. 

Adjustments. — Air  valves,  of  all  types,  require  teplacement 
when  the  wear  allows  the  air  to  leak  through.  This  air  leakage 
reduces  the  amount  of  scavenging  air  and  its  pressure,  which  is 
seldom  over  4  pounds  gage.  If  the  pressure  is  lowered  but 
slightly  below  its  normal  value,  the  air  will  be  insufficient  to 
completely  scavenge  the  cylinder  of  exhaust  gases.  This  air 
valve  leakage  invariably  causes  loss  of  power,  increased  fuel  con- 
sumption and  a  smoky  exhaust. 

Crankshaft  Air  Seal. — Any  inclosed  crankcase  engine  must 
have  some  means  of  preventing  the  air  from  blowing  out  along 
the  shaft.  Some  builders  make  use  of  a  stuffing-box  arrange- 
ment at  the  outer  end  of  the  main  bearings,  Fig.  280.  With  this 
design  the  bearing  cap  must  make  an  air-tight  joint  with  the 
lower  part  of  the  bearing  or  housing.  It  is  better,  in  case  of  re- 
newing the  shims,  to  use  either  a  paper  or  a  thin  rubber  gasket. 
It  is  well-nigh  impossible  to  secure  air-tightness  when  using 
copper  or  tin  shims. 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  355 

In  replacing  the  stuffing-box  packing,  square  duck  packing  or 
braided  hemp,  well  soaked  in  oil  and  graphite,  is  excellent.  In 
drawing  up  the  gland,  it  is  not  necessary  to  exert  much  pres- 
sure; the  2  or  3  pounds  air  pressure  does  not  require  much 
gland  pressure.  If  the  gland  is  drawn  up  tight,  a  groove  will 
gradually  develop  on  the  shaft. 

A  few  engines  are  equipped  with  an  air-sealing  device  at  the 
inner  face  of  the  main  bearing.  This  is  usually  in  the  form  of  a 
brass  plate  placed  between  the  crank  web  and  the  main  bearing 


FIG.  280. — Stuffing  box  air  seal. 

face.  It  has  a  close  fit  with  the  shaft  and,  if  provided  with 
springs  to  keep  it  against  the  bearing,  will  prove  effective.  The 
objection  to  this  device  is  that  it  is  hard  to  replace  when  made 
in  one  piece,  as  is  usually  done.  This  requires  the  removal  of 
flywheel  and  bearing;  but  it  should  be  renewed  as  soon  as  the  leak- 
ing air  causes  the  oil  to  blow  out  of  the  bearing.  It  is  possible 
to  replace  this  without  the  removal  of  the  flywheel  by  making 
the  ring  in  two  pieces.  The  Fairbanks-Morse  Co.  now  furnishes 
a  two-piece  ring  for  replacement.  Where  the  one-piece  replace- 
ment ring  is  supplied  by  any  particular  manufacturer,  the  ring 
can  be  split.  By  removing  the  bearing  liners,  the  two  ring  halves 
can  be  brazed  together.  Another  method  of  emergency  replace- 
ment is  the  use  of  a  ring  of  V-shaped  leather,  Fig.  281.  This  cir- 
cle can  be  cut  in  two  to  place  it  on  the  shaft  and  the  ends  secured 


356 


OIL  ENGINES 


by  fine  wire.  A  coiled  steel  spring  can  then  be  arranged  around 
the  shaft,  resting  in  the  V.  The  spring  forces  the  leather  against 
the  web  and  the  air-sealing  ring,  preventing  any  air  leaks.  The 
leather  wears  rather  rapidly  but  has  solved  the  difficulty  in  more 
than  one  plant  where  the  brass  sealing  ring  began  to  leak.  This 
sealing  ring  takes  the  side  thrust  of  the  cranks,  and,  because  of 
this,  the  leather  cannot  be  recommended  for  a  permanent  re- 
placement. Even  with  the  standard  sealing  rings  the  wear,  due 


Leather  _.- 
Ring--' 

FIG.  281. — Leather  air  seal. 


to  the  side  thrust  of  the  shaft,  is  rather  heavy.  In  time  this 
causes  excessive  clearance,  which  must  be  corrected  by  inserting 
thin  brass  or  steel  shims  between  the  sealing  ring  and  the  crank 
web.  The  ring  springs  will  hold  the  shims  into  place.  These 
shims  wear  rapidly,  and  the  sheet-steel  ones  last  much  longer 
than  the  brass. 

The  important  thing  to  remember  is  that  the  air  seal  must  be 
effective,  otherwise  the  oil  film  will  be  blown  off  the  shaft.  This 
is  more  likely  to  happen  on  a  ring-oiling  bearing  than  on  a  force- 
feed  type  and  will  invariably  result  in  a  hot  bearing. 

Air  Seal  in  Open-frame  Engines. — In  engines  with  an  open 
frame,  and  using  the  front  of  the  cylinder  for  the  air  compressor,  the 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  357 

troubles  of  the  inclosed  frame  are  largely  eliminated.  The  points 
requiring  attention  are  the  air  valve  and  the  piston  rod  stuffing- 
box.  The  latter  has  a  marked  habit  of  wearing,  due  to  the 
pressure  of  the  rod  when  the  crosshead  is  not  in  alignment. 
In  such  cases  it  is  practically  impossible  to  keep  the  packing  in 
condition.  A  good  way  to  tell  when  the  stuffing-box  needs  re- 
packing is  the  presence  of  air  bubbles  mixed  with  the  oil  on  the 
piston  rod.  If  the  leak  is  bad,  the  air,  jetting  out  around  the 
rod,  will  blow  the  oil  entirely  off  the  rod.  Metallic  packing  rings 
have  been  used  on  the  rod  with  some  slight  success;  taken  all 
in  all,  nothing  can  eclipse  the  old  diagonal  duck  and  rubber 
square  packing.  In  inserting  the  packing,  the  rings  should  be 
cut  diagonally  and  the  joints  staggered.  An  oil  pipe  should  be 
located  over  the  rod  immediately  in  front  of  the  stuffing-box; 
it  is  imperative  that  the  rod  receive  positive  lubrication. 


FIG.  282. — Two  piece  main  bearing. 

Main  Bearings. — In  the  low-pressure  engine  three  classes  of 
bearings  are  commonly  employed,  as  shown  in  Figs.  282  to  285. 
Figure  282  is  a  type  best  adapted  to  engines  below  50  or  60  h.p. 
per  cylinder.  It  allows  the  wear  to  occur  at  the  center  of  the 
bottom  shell,  which  is  placed  at  a  45-degree  angle.  Conse- 
quently, to  take  up  a  slight  wear,  it  is  only  necessary  to  remove  a 
shim  or  two  from  between  the  two  shells.  This,  of  course,  ap- 
plies to  the  smaller  size  engines.  Much  bearing  wear  causes  the 
piston  to  increase  the  cylinder  clearance,  lowering  the  compres- 
sion. To  partly  remedy  this,  thin  shims  should  be  inserted  under 
and  back  of  the  lower  shell,  bringing  the  shaft  center  back  to  its 
original  position.  This  particular  bearing  is  lubricated  by  a  me- 
chanical oil  pump,  the  oil  flowing  down  into  the  interior  of  the 


358 


OIL  ENGINES 


engine  frame.     Figure  283  is  the  same  type  of  bearing,  with  the 
addition  of  an  oil  cellar  and  an  oiler  chain. 

Figure  284  is  a  bearing  quite  generally  used  on  both  vertical 
and  horizontal  engines.     In  the  horizontal  engine  the  direction  of 


FIG.  283. — Main  bearing  with  chain  oiler. 

pressure  is  against  the  front  side  of  the  bearing.  Both  the  upper 
and  the  lower  halves  wear  oblong;  consequently  only  a  small 
amount  of  wear  can  be  compensated  for  by  means  of  shims.  If 


FIG.  284. — Main  bearing. 

the  engineer  desires  to  eliminate  all  play  in  the  bearings,  it  will 
be  necessary  to  replace  these  bearing  shells  quite  often.  Due  to 
this,  the  bearing  is  suitable  for  the  smaller  sizes  of  horizontal 
engines  only. 

For  vertical  engines  this  is  the  most  acceptable  bearing.  The 
pressure  is  always  downward,  and  the  wear  occurs  uniformly  on 
the  lower  shell.  It  is  then  an  easy  matter  to  shim  this  shell  back 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  359 

to  its  original  position.  On  a  single-cylinder  vertical  engine,  to 
shim  up  the  shell  it  is  necessary  to  jack-up  the  shaft  from  the 
outside.  The  jacks  should  be  placed  under  the  flywheels,  or,  if 
it  is  impossible  to  do  this,  wood  blocks  with  a  V  cut  into  their  up- 
per side  should  be  placed  under  the  shaft  where  it  extends  beyond 
the  wheels.  By  setting  the  jacks  under  the  blocks,  the  shaft 


FIG.  285. — Munciejoil  engine  main  bearing,  quarter-box^type. 

may  be  raised  with  ease.  Before  jacking-up  the  shaft,  if  the  en- 
gine is  a  belted  unit,  the  belt  should  be  removed  so  that  there  will 
be  no  outside  force  acting  on  the  engine.  In  a  three-  or  four- 
cylinder  engine,  a  jack  should  be  placed  under  the  center  crank- 
pin  box  to  assist  in  raising  the  shaft. 


360  OIL  ENGINES 

The  quarter-box  bearing,  Fig.  285,  when  used  on  horizontal 
engines,  is  very  attractive  from  the  operator's  viewpoint.  It  is 
customary  to  have  the  wedge  on  the  front  side  only.  This  takes 
care  of  all  adjustments  since  the  direction  of  pressure  is  in  variably 
toward  the  front  side  of  the  bearing.  This  being  true,  it  is  not 
essential  to  have  the  rear  quarter-box  adjustable.  Ordinarily, 
the  front  and  bottom  of  the  bearing  are  made  in  one  piece.  The 
weight  of  the  flywheel  and  shaft  wear  the  bottom  only  a  slight 
amount,  and  usually  this  wear  will  not  require  attention  for  some 
years.  It  is  very  easy  to  keep  the  bearing  snug  since  all  that 
need  be  done  is  to  take  up  on  the  front  wedge  bolts.  This  should 
never  be  done  when  the  engine  is  running. 

Some  engine  builders  reverse  the  position  of  the  wedge,  placing 
it  at  the  rear  side.  This  does  not  allow  adjustment  for  wear, 
but  merely  enables  the  engineer  to  reduce  the  shaft  play  by 
bringing  this  side  box  up  against  the  shaft. 

Various  attempts  have  been  made  to  water-cool  the  main 
bearings,  Fig.  285.  Since  there  is  no  reversal  of  pressure,  the 
bearings  will  run  warmer  than  in  case  of  a  steam  engine.  The 
water-cooling  involves  complicated  pipe  lines  and  valves,  and 
,  it  is  difficult  to  take  care  of  the  piping.  If  a  bearing  requires 
water-cooling,  it  is  proof  that  the  bearing  surface  is  not  liberal 
enough  and  the  pressure  per  sq.  inch  is  too  high. 

Figure  272  shows  a  bearing  that  was  the  favorite  in  the  earlier 
days  of  the  oil  engine  and  is  still  used  by  a  few  builders.  This 
bearing  housing  is  in  the  form  of  a  flange  which  is  bolted  to  the 
engine  frame.  The  bearing  is  a  cylindrical  one-piece  bushing 
without  means  of  adjustment.  In  case  of  any  considerable 
wear,  the  sole  remedy  is  replacement  of  the  entire  bushing. 
The  bearing  is  lubricated  by  means  of  a  mechanical  oil  pump, 
assisted  by  a  ring  oiler,  which  dips  into  a  cellar  below  the  bushing. 
Since  the  bearing  wear  must  be  of  some  extent  before  the  engineer 
feels  that  replacement  is  justified,  air  leaking  along  the  shaft  is 
a  trouble  often  encountered.  The  air-seal  ring  should  prevent 
the  air  leaks,  but  the  "jump"  of  the  shaft,  due  to  the  worn 
bearing,  will  wear  the  ring  until  it  is  valueless. 

Adjustments. — In  making  bearing  adjustments  the  operator 
should  keep  in  mind  the  fact  that  the  shaft  must  be  leveled  up 
true  in  respect  to  the  housing.  To  line  them  up  with  the  cylinder, 
a  good  plan  is  to  place  the  engine  on  both  dead-centers  and  see 
if  the  connecting-rod  is  in  the  center  of  the  crank  throw.  In 
case  of  general  repairs  center  lines  should  be  established. 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  361 

The  question  is  frequently  asked  as  to  what  amount  of  play 
should  be  allowed  between  the  shaft  and  upper  bearing  cap. 
If  the  bearing  be  one  where  the  cap  does  not  carry  any  of  the 
pressure,  a  good  plan  is  to  loosen  the  cap,  or  tighten  it,  until 
the  shaft  can  be  " jumped"  about  one  or  two  hundredths  of  an 
inch.  Side  play  between  bearing  face  and  crank  web  can  be 
from  \i oo  to  ^4  inch  without  danger,  though  the  first  value  is 
one  that  conforms  more  closely  to  good  engineering. 

The  real  difficulty  in  main  bearings  is  the  question  of  lubrica- 
tion. The  suggestions  outlined  in  the  care  of  Diesel  bearings 
apply  with  equal  force  to  the  low-pressure  engine.  Even  with 
an  oil-cellar  design  stream  lubrication  is  highly  desirable.  The 
practice  many  engineers  have  of  using  the  same  oil  for  months 
without  refiltering  is  open  to  severe  criticism.  No  engine  bearing 
will  stand  up  long  if  dirty  oil  be  used.  For  a  small  plant,  where 
first  cost  of  accessories  is  of  serious  moment,  a  5-gallon  can  with 
a  false  bottom  and  with  the  upper  part  filled  with  waste  makes 
a  good  filter.  A  high-grade  filter,  purchased  from  a  filter  manu- 
facturer, will  pay  for  itself  in  a  short  time,  in  oil  saving  alone. 

Another  matter  of  doubt  is  how  hot  an  engine  bearing  may 
become  before  the  engineer  should  consider  it  dangerous.  In 
all  two-stroke-cycle  engines  the  bearings  will  run  warmer  than 
on  a  four-stroke-cycle  engine,  since  the  direction  of  pressure  is 
not  reversed;  and,  as  a  result,  the  lubrication  is  not  so  good.  In 
case  the  bearing  becomes  too  hot  to  touch  with  the  fingers,  the 
load  should  be  thrown  off  and  the  engine  run  slowly  while  the 
bearing  cools  off.  It  is  usually  noticeable  that  on  a  single- 
flywheel  engine  the  bearing  next  to  the  flywheel  runs  warmer  than 
the  other  bearings.  Many  new  engines  have  this  bearing  slightly 
higher  than  the  other  one,  to  compensate  for  the  wear.  On 
engines  already  in  service  the  hot  bearing  is  probably  due  to  in- 
creased wear  caused  by  the  extra  weight  of  the  flywheel. 

Crankshafts. — Investigation  of  crankshaft  failures,  in  most 
instances,  reveals  that  the  fracture  occurred  at  the  junction 
of  the  shaft  and  crank  throw,  or  at  the  junction  of  the  crank 
throw,  or  web,  and  crank  pin.  This  liability  of  fracture  can  be 
largely  reduced  by  more  liberal  fillets  at  these  points.  The 
danger  of  fractures  will  never  be  totally  eliminated  as  long  as 
engineers,  on  starting,  allow  too  much  oil  to  be  injected  into  the 
cylinder.  Not  all  of  this  oil  burns  on  the  first  stroke.  Some 
is  trapped  in  the  cylinder  and,  mixing  with  the  air  on  the  com- 


362  OIL  ENGINES 

pression  stroke,  preignites  long  before  the  piston  reaches  dead- 
center.  To  better  protect  the  engine  against  the  operator's 
carelessness  it  is  good  practice  to  attach  a  safety  valve  to  the 
cylinder.  A  great  many  engines  are  so  equipped,  and  all  engines 
have  a  pet-cock  or  indicator  opening  that  can  be  used  to  connect 
the  safety  or  relief  valve  to  the  cylinder. 

There  seems  to  be  a  deep-rooted  belief,  held  by  many  engineers, 
that  a  crankshaft  must  be  scrapped  at  the  least  sign  of  grooving 
or  cutting  at  the  bearings.  Since  a  crankshaft  represents  a 
considerable  per  cent,  of  an  engine's  total  cost,  effort  should 
always  be  exerted  to  repair  the  old  shaft.  If  the  grooving  is 
slight,  the  bearing  cap  should  be  removed  as  should  also  the 
entire  bearing  shell.  Wooden  blocks  should  be  inserted  to 
prevent  the  shaft  from  shifting.  A  file,  used  while  the  shaft  is 
turned  slowly  by  hand,  will  smooth  up  cuts  that  are  rather  deep. 
When  the  defect  is  too  far  developed  to  be  cured  by  this  method, 
the  shaft  should  be  shipped  to  a  good  machine  shop  and  a  cut 
taken  off  of  it  at  the  journals.  Where  this  is  done,  it  becomes 
necessary  to  rebabbitt  the  bearing  shells  to  the  now  smaller 
diameter  of  the  shaft. 

Flywheels. — Small  oil  engines  up  to  about  100  h.p.  make 
use  of  a  solid  rim  flywheel,  the  hub  being  either  split  at  one 
side  or  at  both  sides,  according  to  the  tastes  of  the  builder. 
In  placing  a  flywheel  onto  the  shaft,  iron  wedges  should  be  driven 
into  the  splits  at  the  hub;  a  wedge  should  be  used  both  on  the 
outside  and  on  the  frame  side  of  the  hub  in  order  to  open  the  split 
evenly.  The  shaft  should  be  carefully  cleaned  with  gasolene, 
and,  if  any  rust  is  present,  this  should  be  removed  by  emery 
cloth.  The  shaft  should  be  well  oiled  and  the  flywheel,  after 
being  blocked  up  level  with  the  shaft,  slipped  on.  The  iron 
wedges  usually  open  up  the  hub  enough  to  allow  the  wheel  to 
slip  on  easily.  After  the  wheel  is  on  far  enough  to  prevent  it 
tilting,  rotation  of  the  wheel  will  cause  it  to  slip  along  the  shaft 
much  more  freely.  In  tightening  the  hub  bolts  after  the  wheel 
is  in  place,  the  same  tension  should  be  given  each  bolt ;  the  nuts 
should  be  tightened  slowly,  working  them  down  uniformly. 
If  one  bolt  is  drawn  up  before  the  others  have  been  touched,  the 
wheel  may  cock  a  little. 

A  close  observer,  in  visiting  oil  engine  plants,  will  notice  the 
practically  universal  habit  of  the  flywheel's  running  out  of  true. 
In  some  cases  it  is  because  the  builder  fails  to  true  the  wheel  up 


ENGINE  FRAMES,  BEARINGS,  SHAFTS,  FLYWHEELS  363 


properly.  Usually,  though,  it  is  caused  by  the  erector  cocking 
the  wheel  when  pulling  it  on  the  shaft.  While  a  wheel  in  this 
shape  is  not  dangerous,  still  it  detracts  from  the  appearance  of 
an  otherwise  attractive  power  plant.  Many  suggestions  have 
been  offered  in  regard  to  the  best  way  to  correct  this.  Some  en- 
gineers loosen  up  the  hub  and  insert  a  thin  shim  around  the  shaft 
on  the  "out"  side.  It  is  seldom  that  this  does  any  good,  and  it 
is  not  safe  since  the  shims  always  work  loose.  Others  shim  up 
under  the  key  on  one  side  of  the  hub  and  attempt  to  throw  the 


.Hammer 

I     „ 

Strike  here' 


FIG.  286. — Key  puller. 


FIG.  287.— Key  puller. 


wheel  straight.  Even  if  successful,  the  flywheel  is  left  in  an 
insecure  position  since  now  only  the  key  holds  it.  The  most 
approved  way  is  to  peen  the  rim  until  the  wheel  runs  true.  The 
engineer  should  mark  the  part  of  the  rim  that  runs  out  with  chalk. 
This  will  indicate  the  particular  section  of  the  wheel  that  must 
be  peened.  The  engine  should  be  slowed  down  to  about  30  to 
50  r.p.m.  and  a  5-pound  hammer  used  against  the  rim  at  the 
chalked  place.  The  rim  should  not  be  struck  with  much  force. 
Presevarence  with  the  hammer  will  bring  the  wheel  back  into 
line,  and  the  engine  will  run  without  the  slightest  variation  in 
the  rim  travel. 


364  OIL  ENGINES 

Withdrawing  a  wheel  key  is  probably  the  hardest  undertaking 
around  an  engine.  This  is  simply  due  to  the  lack  of  proper  facili- 
ties. The  average  engineer  drives  a  chisel  between  the  key-head 
and  the  wheel  hub,  mars  up  the  shaft  and  gets  disgusted  with  the 
job.  A  key  on  an  oil  engine  should  be  drilled  and  tapped  for  a 
" pull-out"  bolt.  If  this  is  not  already  done,  the  operator  should 
do  it,  for  it  is  not  difficult.  Then  a  piece  of  iron  can  be  made 
U-shaped  and  tapped  for  the  bolt.  Placing  this  U  bracket  over 
the  shaft,  Fig.  286,  the  bolt  can  be  drawn  taut,  and  a  sharp  blow 
on  the  key  will  start  it.  A  device  like  Fig.  287  can  be  used  on 
the  smaller  engines  with  success.  A  3^X2  in.  flat  strip  of  iron 
some  16  inches  long  is  bent  at  the  end  A.  The  other  end  has  a 
square  hole  which  is  placed  over  the  head  of  the  key  as  shown. 
By  striking  with  a  hammer  at  A  the  key  can  be  loosened. 


CHAPTER  XXII 

GOVERNORS,  FUEL  PUMPS  AND  INJECTION  NOZZLES, 
TYPES,  ADJUSTMENTS  AND  REPAIRS 

Governors. — If  a  smooth-running,  efficient  engine  is  to  be  pro- 
duced, the  designs  of  the  governor  and  the  fuel  pump  must  be 
co-ordinated.  Indeed,  many  engine  builders  have  united  these 
two  mechanisms  into  one  design.  For  this  reason  it  is  advisable 
that  any  discussion  of  a  particular  fuel  pump  should  be  incor- 
porated into  the  discussion  of  its  respective  governor. 

Hit-and-miss  Governing. — The  hit-and-miss  method  of  gov- 
erning has  been  tried  out  on  the  low-pressure  oil  engine,  but  it 
has  never  proved  successful.  With  this  arrangement,  the  scav- 
enging air  charge  blows  into  the  cylinder  on  the  idle  as  well  as  on 
the  power  cycles.  This  results  in  the  removal  of  a  great  amount 
of  heat  from  the  hot  head,  the  head  generally  becoming  so  cold 
as  to  be  very  irregular  in  the  ignition  of  the  fuel  charge.  When 
the  fuel  charge  does  ignite,  the  low  temperature  of  the  bulb  results 
in  a  large  heat  transfer  from  the  hot  gases  to  the  cold  bulb.  This, 
of  course,  lowers  the  engine's  efficiency.  There  is  a  still  more 
serious  defect.  The  irregularity  of  the  explosions,  and  the  miss- 
firing  when  the  governor  does  inject  a  fuel  charge,  produces 
marked  "  hunting. "  This  destroys  the  engine's  usefulness  in 
any  situation  where  close  regulation  is  demanded. 

With  the  price  of  gasolene  advancing,  as  it  has  been  doing  the 
past  few  years,  there  will  be  a  large  field  for  cheap  low-pressure 
engines  of  small  powers  capable  of  handling  distillates.  The 
kerosene  or  modified  gasolene  engine  will  not  burn  even  kerosene 
in  a  satisfactory  manner  where  the  load  is  variable.  It  would 
seem  that  the  hot-bulb  engine  must  be  the  type  adopted.  Since 
it  must  be  low  in  cost,  the  present-day  forms  of  governors  cannot 
be  used.  The  hit-and-miss  principle  is  the  logical  choice.  To 
accomplish  this,  probably  the  hot  tube,  formerly  used  on  the 
gasolene  engine,  will  be  the  ignition  device  adopted.  This  re- 
sembles the  present  day  hot-bulb  with  the  exception  that  the 
torch  is  always  maintained  lighted.  The  use  of  a  permanent 
flame  would  eliminate  all  the  objections  mentioned  above.  On 

365 


366 


OIL  ENGINES 


engines  above  10  h.p.  the  advantages  of  the  quantitative  governor 
'over  the  hit-and-miss  type  make  its  use  advisable  even  though 
more  costly. 

Classes  of  Governors. — The  vast  majority  of  low-pressure  oil 
engines  use  a  quantitative  governor,  wherein  the  amount  of  fuel 
injected  each  cycle  is  regulated  to  conform  to  the  power  demands. 

This  may  be  accomplished  by  either  of  two  means.  By  the 
first  method  the  stroke  of  the  pump  plunger  is  regulated,  thereby 
delivering  a  varying  quantity  of  oil  to  the  nozzle.  The  second 
method  consists  of  some  arrangement  whereby  the  opening  of 
the  pump  suction  valve,  or  of  a  by-pass  valve,  limits  the  fuel  en- 
tering the  cylinder  to  the  amount  actually  required  to  carry  the 
load.  Both  in  effect  might  be  compared  to  the  automatic  cut-off 
governor  so  popular  with  high-speed  steam  engine  builders. 

While  a  few  builders  employ  fly-ball  governors  similar  to  those 
used  on  throttling  steam  engines,  the  majority  have  adopted 
shaft  governors  of  either  the  centrifugal  or  inertia  type.  The  use 
of  the  shaft  governor  allows  the  eccentric  to  act  directly  on  the 
pump  mechanism,  and  this  type  is  more  favorably  received  by 
operating  engineers. 


FIG.  288. — Muncie  oil  engine  governor. 

Muncie  Oil  Engine  Co.' s  Governor. — The  form  of  governor 
shown  in  Fig.  288  is  "used  extensively  with  certain  modifica- 
tions. This  particular  gov.ernor  is  that  used  on  the  Muncie 
oil  engine.  It  consists  of  two  weighted  arms  pivoted  at  A  to  a 
disk  B  that  is  keyed  to  the  crankshaft.  The  extensions  of  these 
arms  are  pivoted  at  the  points  C  to  the  eccentric  plate  which  is 
held  in  guides  that  are  a  part  of  the  disk  B.  The  disk  B  has 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      367 

slots  in  it  to  allow  the  lever  pivots  at  C  to  project  through  into 
the  eccentric  plate.  As  the  engine  comes  up  to  speed,  the  arms 
tend  to  move  outward,  this  movement  being  resisted  by  the  ten- 
sion springs.  If  the  load  on  the  engine  is  decreased,  the  engine 
speeds  up  and  the  weights  overcome  the  spring  tension  and  move 
outward,  due  to  the  increased  centrifugal  effect.  This  move- 
ment of  the  arms  continues  until  the  increased  spring  tension 
equalizes  the  centrifugal  force  due  to  the  increased  speed.  The 
movement  of  the  arms  causes  the  eccentric  to  slide  in  the  guides 
and,  consequently,  alters  the  stroke  of  the  fuel  pump.  If  the 
speed  decreases,  the  movement  of  the  arms  and  eccentric  is, 
of  course,  the  reversal  of  the  above,  resulting  in  the  pump  stroke, 
bngthening. 

In  operation,  this  governor  is  practically  trouble-proof.  A 
point  to  be  remembered  is  the  necessity  of  keeping  the  pivots 
and  the  guides  well  oiled.  The  guides  will  quite  likely  collect 
dirt  and  grit.  This  will  hinder  the  movement  of  the  eccentric, 
and  the  engine  will  tend  to  race.  The  governor  should  be  wiped 
with  a  rag  or  wiping  cloth  each  time  the. engine  is  stopped. 
Every  few  months  the  governor  should  be  dismantled  and  every 
part  thoroughly  cleaned  and  oiled.  If  the  guides  seem  rough, 
they  should  be  smoothed  with  a  scraper.  An  engine  must  be 
in  service  a  number  of  years  before  much  play  develops  in  the 
guides.  When  this  does  occur,  the  guides  should  be  removed 
and  the  base  filed  down.  If  there  is  side  play,  a  copper  strip 
can  be  placed  between  the  guide  and  the  disk  and  flanged  up  so 
that  it  fills  the  space  between  the  guide  and  the  eccentric.  It  is 
also  a  good  plan  to  keep  on  hand  a  spare  set  of  governor  springs. 
Some  operators  have  the  idea  that  any  spring  will  meet  the  re- 
quirements. In  governor  construction,  the  spring  must  be  of  a 
length  and  the  wire  of  a  cross-section  such  as  will  allow  the  gover- 
nor weights  to  be  in  equilibrium  in  any  position.  If  the  spring 
has  too  many  coils,  even  though  of  the  correct  size  wire,  the 
governor  may  "hunt,"  and  the  engine  may  even  have  a  higher 
speed  at  full  load  than  at  no  load.  This  is  true  where  there  is 
any  inertia  effect  from  the  arms.  There  are  few  shaft  governors 
that  do  not  display  some  inertia  effect  in  operation. 

While  it  is  possible  to  move  the  disk  on  the  shaft,  it  is  not 
advisable  for  the  inexperienced  engineer  to  attempt  to  alter  the 
setting.  The  builders  always  set  the  eccentric  at  the  point 
where  the  oil  injection  should  best  begin  when  the  average 


368 


OIL  ENGINES 


gravity  fuel  oil  is  used.  Even  though  a  different  oil  be  used,  the 
operator  can  seldom  better  the  conditions;  none  but  an  expert 
should  make  this  adjustment.  However,  when  an  engineer  is 
meeting  with  preignition  trouble  due  to  light  oils,  there  is  no 
reason  why  he  should  not  experiment  with  the  setting,  using 
an  off-set  key  to  secure  any  alteration  in  the  position  of  the  disk. 
This  governor  belongs  to  that  class  wherein  the  point  of  be- 
ginning of  oil  injection,  as  well  as  the  amount  of  oil  injected,  which 
depends  on  the  length  of  pump  stroke,  is  altered  as  the  load 
changes.  In  other  words,  speaking  in  steam  engine  nomen- 
clature, both  the  angular  advance  and  the  eccentricity  change. 


FIG.  289.  FIG.  290. 

Action  of  Muncie  governor. 

The  action  of  this  governor  may  be  understood  from  Figs. 
289  and  290.  In  Fig.  289  the  full  lines  show  the  eccentric  position 
at  low  load.  The  crankshaft  center  is  at  0  and  the  center  of  the 
eccentric  at  A .  The  crank  is  at  an  angle  a  from  the  center  line 
XY.  In  this  position  fuel  injection  is  just  commencing,  as  in- 
dicated by  the  contact  of  the  eccentrics  with  the  push-rod  B 
of  the  fuel  pump.  Under  full  load  the  eccentric'is  moved  to  the 
position  shown  in  Fig.  290,  the  eccentric  center  being  then  at 
A'  and  contact  with  the  push-rod  being  made  at  B'.  These 
same  positions  are  shown  dotted  in  Fig.  289. 

In  the  first  position  of  the  eccentric  the  injection  of  oil  begins 
when  the  crank  is  a  degrees  from  rear  dead-center,  and  the  total 
movement  of  the  plunger  is  C.  In  the  new  position  of  the 
eccentric,  the  crank  is  a  +  6  degrees  from  dead-center  when  the 
injection  begins,  while  the  total  plunger  movement  is  C'.  It 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      369 

is  apparent  that  the  eccentricity  or  throw  of  the  eccentric  in 
Fig.  289  is  greater  than  C,  but  the  difference  represents  the 
movement  of  the  eccentric  before  it  strikes  the  push-rod  or 
the  pump  plunger  and  might  well  be  called  the  "  lap  "  of  the  pump. 

In  operation,  on  low  loads,  the  angle  of  advance  of  the  eccen- 
tric is  such  that  the  fuel  is  injected  somewhat  later  in  the  com- 
pression stroke  than  on  full  load,  the  crank  being  about  15  degrees 
ahead  of  the  rear  dead-center  and  the  change  in  crank  position 
being  about  15  degrees.  This  results  in  poor  combustion  and  a 
smoky  exhaust  since  the  oil  charge  has  insufficient  time  to  vapor- 
ize and  burn.  With  the  use  of  kerosene  or  light  distillates  this 
objection  cannot  be  raised  since  the  rate  of  vaporization  is  very 
rapid  even  at  a  low  temperature.  On  full  load  the  point  of 
injection  advances  to  practically  30  degrees  ahead  of  rear  dead- 
center.  With  heavy  fuel  oil  or  "tops"  this  point  of  admission 
is  not  objectionable;  in  fact,  it  is  an  advantage  since  there  is  a 
greater  time  interval  before  dead-center  is  reached  for  the  heavy 
oil  to  completely  vaporize  and  ignite.  But  with  light  oils,  such 
as  distillates  or  a  crude  containing  a  considerable  percentage 
of  light  hydrocarbons,  this  early  injection  causes  preignition. 
Such  preignition  often  becomes  so  heavy  that  it  is  impossible 
to  eliminate  the  knock  by  using  water  injection;  for,  if  enough 
water  is  used  to  prevent  preignition,  the  cylinder  will  be  flooded 
and  the  hot  bulb  cooled  to  an  extent  that  combustion  is  entirely 
suppressed.  This  early  injection  of  the  fuel  charge  is  not  re- 
quired, and  in  actual  operation  the  skilled  engineer  makes  the 
admission  occur  later  by  manipulation  of  the  fuel  pump  regulator 
which  will  be  mentioned  on  succeeding  pages. 

Muncie  Fuel  Injection  Pump. — The  fuel  pump  used  on  all  the 
Muncie  engines,  with  the  exception  of  a  few  of  the  larger  sizes,  is 
shown  in  Fig.  291.  The  stroke  of  the  pump  plunger  is  controlled 
by  the  eccentric  push-rod,  as  outlined  in  Fig.  289.  The  spring  A 
is  seated  against  a  collar  B  on  the  pump  plunger  and  serves  to 
move  the  plunger  on  the  outward,  or  suction,  stroke.  The 
eccentric  push-rod,  of  course,  actuates  the  plunger  on  the  dis- 
charge stroke;  any  change  of  the  shaft  governor,  by  altering  the 
throw  of  the  eccentric,  causes  an  alteration  in  the  plunger 
movement. 

This  pump  is  provided  with  a  hand-controlled  speed-changing 
device  mounted  on  the  body  of  the  pump.  It  consists  of  a  link  C 
which  is  threaded  at  one  end  to  receive  a  wing-nut  D  and  which  is 

24 


370 


OIL  ENGINES 


slotted  at  the  other  end  to  engage  a  pin  E  on  the  pump  plunger. 
If  it  is  desired  to  lower  the  speed,  the  wing-nut  is  screwed  up, 


FIG.  291. — Muncie  fuel  pump. 

shortening   the  link  and  lessening  the  outward   movement  of 
the  plunger.     The  link  is  provided  with  a  lock-nut  F  that  serves 


WLter  Suction  Line  . 

FIG.  292. — Muncie  oil  engine,  fuel  and  water  injection  pump. 

to  hold  the  link  in  the  desired  position.     By  using  this  adjust- 
ment the  plunger  travel  can  be  reduced  until  practically  no  oil 


GOVERNORS,  FUELPUMPS,  INJECTION  NOZZLES      371 

is  injected  into  the  engine  so  that  an  excellent  speed  control  is 
obtained.  It  has  another  important  advantage  that  is  of  more 
benefit  than  is  its  speed-regulating  ability.  This  is  its  use  in 
changing  the  point  of  injection,  which  principle  will  be  discussed 
later  in  the  chapter. 

The  pump  is  simple  in  design  and  requires  but  little  attention, 
but  probably  some  degree  of  fuel  control  has  been  sacrificed  in 
obtaining  this  simplicity.  The  valves  are  steel  balls;  to  reseat 
these,  a  sharp  blow  with  a  hardwood  stick  and  a  mallet  will  usu- 
ally be  all  that  is  needed.  The  lift  of  the  ball  valves  should  be 
limited  to  J-^2  inch  by  dressing  off  the  plug  seat  until  this  value  is 
attained.  The  packing  around  the  plunger,  as  in  all  pumps,  in 
time  wears  out.  In  replacing  the  worn  rings,  they  should  be  well 
soaped  before  being  inserted  into  the  stuffing-box.  It  is  never 
advisable  to  screw  down  very  hard  on  the  gland  as  the  side  pres- 
sure of  the  rings  will  cause  the  pump  plunger  to  stick,  or  at  least 
to  score. 

On  the  larger  Muncie  engines  the  company  has  brought  out  a 
combined  fuel  and  water  injection  pump,  Fig.  292.  This  unit 
consists  of  a  heavy  bracket  pump  casting  with  two  cavities  for 
the  fuel  and  water  plungers.  The  pump  plunger  6  is  actuated 
directly  by  the  eccentric  push-rod  a.  The  push-rod  has  an  ad- 
justable end  which  allows  the  clearance  between  rod  and  plunger 
to  be  adjusted.  Due  to  the  pounding  of  the  rod  end,  the  clear- 
ance increases  and  should  be  checked  at  least  every  two  months. 
To  make  the  adjustment  the  engineer  should  proceed  as  follows: 
Set  the  fuel  pump  plunger  out  to  its  extreme  forward  or  suction 
position  by  unloosening  the  adjusting  or  regulator  rod.  Loosen 
the  governor  springs  and  block  the  governor  weights  to  their 
maximum  outward  position  so  that,  as  the  crankshaft  is  turned, 
no  motion  is  given  to  the  push-rod — the  eccentric  is  now  concen- 
tric with  the  shaft.  The  adjusting  stud  should  now  be  set  to 
allow  the  clearance  between  stud  and  pump  plunger  to  be  %2 
inch.  The  lock-nut  should  be  screwed  up  and  the  governor 
springs  tightened  into  place.  The  engine  should  be  started  and 
brought  up  to  maximum  speed  by  manipulating  the  pump  handle. 
At  this  speed,  with  the  governor  weights  at  their  greatest  throw, 
the  plunger  clearance  should  be  ^2  mcn-  If  tne  governor 
weights  do  not  throw  out  enough  to  cut  down  the  throw  of  the 
eccentric,  the  springs  are  too  tight  and  should  be  loosened  a 
slight  amount. 


372 


OIL  ENGINES 


Fairbanks-Morse  Horizontal  Engine  Governor. — Figure  293 
is  a  sketch  of  the  shaft  governor  used  on  the  Fairbanks-Morse 
horizontal  oil  engines  of  25  h.p.  and  under.  It  is  of  the 
well-known  Rites  inertia  type  which  has  been  adopted  by  many 
builders  of  high-speed  steam  engines.  This  governor,  at  first 
glance,  appears  to  be  the  simplest  and  most  reliable  of  all;  how- 
ever, there  are  certain  features  to  be  borne  in  mind.  Since  the 

governor  arm  is  supported  at  one 
point  and  all  the  weight  is  con- 
centrated on  a  line  falling  outside  of 
this  pivot  point,  the  governor  is  out 
of  balance.  All  the  thrust  of  the 
weights  is  against  one  side  of  the 
pivot  or  fulcrum  pin,  and  the 
natural  result  is  wear  of  this  pin  on 
that  one  side,  causing  the  governor 
to  bind.  The  engine,  in  conse- 
quence of  this  binding,  shows 
marked  racing  or  "  hunting," 
especially  on  low  or  varying  loads. 
In  the  Fairbanks-Morse  governor, 
to  eliminate  this  defect,  the  pin  is 
hardened  and  ground,  and  the 
governor  carries  a  hardened  bushing 
into  which  this  pin  fits.  This 
serves  to  reduce  the  wear,  but 
the  friction  between  pin  and  bush- 
ing, produced  by  the  side  thrust 
of  the  weights,  is  considerable. 
If  the  compression  grease  cup  is  not  watched,  the  friction  will 
make  the  governor  very  sluggish  in  action.  In  those  engines 
where  the  design  does  not  embody  a  hardened  bushing,  the 
pin  should  be  given  a  quarter  turn  each  thirty  days.  This  will 
distribute  the  wear  evenly  about  the  entire  periphery  of  the 
pin.  If  a  soft  bushing  is  used,  this,  rather  than  the  pin, 
should  be  turned. 

The  weights  are  held  in  equilibrium  by  a  tension  spring,  and 
the  speed  of  the  engine  is  increased  by  tightening  the  spring. 
The  engine  will  regulate  more  closely  if  the  end  of  the  spring, 
held  in  the  slot  in  the  weight  arm,  is  moved  outward.  Moving 
it  inward  decreases  the  sensitiveness  of  the  governor,  allowing 


FIG.  293. — Governor  of  Fair- 
banks-Morse horizontal  type  Y 
engine. 


GO VERNORS,  FUELPUMPS,  INJECTION  NOZZLES      373 


the  engine  to  have  quite  a  range  in  speed  variation;  but  this  is 
the  proper  way  to  have  the  engine  govern  if  it  is  pulling  an  in- 
dustrial load,  such  as  a  cereal  mill. 

To  dampen  the  action  of  the  governor,  which  is  inherently 
very  sensitive,  some  kind  of  drag  is  used.  In  the  Fairbanks- 
Morse  engine  the  drag  is  introduced  by  the  action  of  a  small 
plunger  A,  Fig.  293,  placed  in  a  recess  in  one  of  the  weights.  The 
outer  end  of  the  plunger  bears  against  a  wrought-iron  angle  bolted 
to  the  inner  face  of  the  flywheel  rim.  The  plunger  is  kept  in 
contact  with  the  angle  iron  by  the  coil  spring  B.  It  is  necessary 


— v 


FIG.  294.  FIG.  295. 

Action  of  Fairbanks-Morse  Rites  governor. 

to  give  this  plunger  considerable  side  clearance  to  allow  it  to 
move  freely.  The  drag  of  the  governor  tends  to  cause  the 
plunger  to  bind  on  one  side  of  the  cavity  at  the  top  and  on  the 
other  side  at  the  bottom  of  the  plunger.  This  wears  the  cavity 
out  of  true  and  causes  the  plunger  to  wedge,  resulting  in  the 
governor  hunting.  If  the  wear  becomes  pronounced,  the  proper 
method  of  adjustment  is  to  drill  the  recess  to  a  larger  bore  and 
turn  up  a  new  plunger  to  fit  it.  Since  it  is  easier  to  make  a 
new  plunger  than  to  enlarge  the  recess,  the  plunger  should  be 
made  of  mild  steel;  it  will  then  receive  all  the  wear  while  the 
recess  will  keep  its  true  shape. 

The  Rites  governor,  also,  advances  the  point  of  injection,  or 


374  OIL  ENGINES 

" admission,"  and  increases  the  eccentricity,  or  the  pump  plunger 
travel,  as  the  load  increases;  see  Figs.  294  and  295.  The  full 
lines  in  Fig.  294  show  the  positions  of  the  crank,  eccentric  and 
weight  arm  at  low  load.  The  eccentricity  is  OA,  and  the  crank  is 
a  degrees  from  dead-center  when  the  eccentric  begins  to  move 
the  push-plunger  B.  It  should  be  understood  that  an  eccentric 
strap  is  used  on  this  governor,  and  the  pump  plunger  receives 
its  motion  from  the  action  of  the  eccentric  strap  and  push-rod. 
The  point  B,  which  represents  the  end  of  the  pump  plunger,  is 
for  clearness  and  simplicity  shown  as  being  in  contact  with  the 
eccentric.  The  weight  arm  and  eccentric  swing  on  the  pivot  C. 
The  positions  under  full-load  conditions  are  shown  in  Fig.  295, 
as  well  as  by  the  dotted  lines  in  Fig.  294.  In  changing  from  low 
load  to  full  load,  the  eccentric  center  moves  from  A  to  A',  and 
the  eccentricity  increases  from  OA  to  OA'.  The  beginning  of 
fuel  injection,  or  admission,  is  made  earlier  since  the  crank  is  now 
a  +  6  degrees  from  rear  dead-center  when  the  eccentric  begins 
to  act  on  the  push-rod.  As  with  the  Muncie  governor,  the  throw 
of  the  eccentric  exceeds  the  pump  plunger  stroke,  the  travel  of 
the  eccentric,  tmtil  the  operating  rod  strikes  the  pump  plunger 
or  push-rod,  being  the  "lap." 

As  mentioned  before,  early  injection  is  advantageous  when 
using  heavy  oil,  as  it  allows  more  time  for  the  oil  to  vaporize; 
consequently,  a  given  size  of  engine  will  carry  a  greater  load  than 
it  would  if  the  governor  did  not  advance  the  injection  admission. 

It  should  be  borne  in  mind  that  the  position  of  the  weight- 
arm  pivot,  relative  to  the  position  of  the  crank  and  the  center  of 
the  eccentric,  largely  determines  the  actual  action  of  the  governor. 
While  the  governor  should  be  designed  to  allow  the  speed  at  no 
load  to  be  above  the  full-load  speed,  it  is  possible,  by  proper  distri- 
bution of  the  weights  and  the  spring  tension,  to  cause  the  engine 
to  speed  up  on  full  load. 

The  relative  positions  shown  in  Figs.  294  and  295  closely  ap- 
proximate those  on  the  governors  in  use.  The  eccentric  is  made 
in  one  piece  with  the  weight  arm,  and  no  means  are  present  to 
change  the  angle  of  advance.  The  pump,  however,  has  a  stop 
whereby  some  adjustment  can  be  made  as  outlined  in  the  dis- 
cussion on  page  387. 

Fairbanks-Morse  Fuel  Pump. — The  fuel  pump  used  with  this 
governor  is  shown  in  Fig.  296.  It  consists  of  a  bracket  pump 
body  into  which  are  fitted  the  valves  and  plunger.  The  plunger 


GOVERNORS,  FUEL  P UMPS,  INJECTION  NOZZLES      375 

is  hardened  and  ground,  and  no  packing  is  used.  The  plunger  is 
forced  to  the  rear  on  the  suction  stroke  by  the  spring  shown.  Its 
suction  travel  is  limited  by  the  plunger  stop  "99."  This  is  pro- 
vided with  a  fibre  tip,  which  wears  and  must  be  renewed  at  in- 
tervals. The  plunger  stop  is  bored  out,  allowing  the  eccentric 
push-rod  to  work  through  it  against  the  end  of  the  pump  plunger. 
The  stop  can  be  screwed  in  or  out,  thereby  adjusting  the  suction 


To  Nozzle 


FIG.  296. — Fairbanks- Morse  type  "Y"  horizontal  engine  fuel  pump. 

travel.  This  alters  the  speed  and  provides  a  means  of  manipu- 
lating the  injection  timing,  as  will  be  discussed  later  in  the  chapter. 
Since  the  Fairbanks-Morse  engine  does  not  use  water  injection, 
the  adjusting  of  this  stop  allows  the  engineer  to  deaden  preigni- 
tion  pounds.  If  the  engine  pounds,  the  screwing-in  of  the  stop 
will  cause  the  preignition  to  cease.  If  the  engine  slows  down  due 
to  overload  or  slow-burning  oil,  the  screwing-out  of  the  stop  will 
cause  the  oil  to  be  injected  earlier  and  in  slightly  greater 
amounts. 

The  suction  and  discharge  valves  are  of  steel  and  are  of  the 
spring-loaded  poppet  type.  The  seats  are  at  an  angle  of  45 
degrees,  while  the  lift  should  not  exceed  ^2  inch.  In  regrinding 


376 


OIL  ENGINES 


these  valves  nothing  but  the  finest  of  emery  flour  or  rotten  stone 
mixed  with  vaseline  should  be  used.  Care  should  be  taken  that 
all  the  parts  are  thoroughly  clean  on  reassembling.  In  tightening 
up  the  cap  lock-nuts,  if  the  operator  is  not  cautious,  the  brazed 
joint  between  the  sleeve  and  the  oil  pipe  will  break. 


FIG.  297.  FIG.  297a. 

FIG.  297. — Fairbanks  Morse  Co.  vertical  type  Y  engine  governor. 
FIG.  297a. — Governor  cam  case. 


'  "OVERFLOW 
'SUCTION 


FIG.  298. — Fairbanks- Morse  vertical  type  Y  engine  fuel  pump  for  three  cylinder 

engine. 

The  fuel  is  pumped  into  the  pump  tank  by  a  plunger  pump 
driven  off  the  eccentric  rocker  shaft.  The  tank  is  fitted  with  a 
sight  glass  and  a  small  gauze  filter.  This  filter  must  be  cleaned 
at  least  twice  each  day  since  the  mesh  is  very  fine  and  the  collec- 
tion of  dirt  soon  stops  the  flow  of  oil. 


GOVERNORS,  FUEL  PUMPS.  INJECTION  NOZZLES      377 

Fairbanks-Morse  Vertical  Engine  Governor. — The  governor 
shown  in  Figs.  297  and  298  is  the  one  used  by  the  Fairbanks-Morse 
Co.  on  their  vertical  type  "Y,"  both  single-  and  multi-cylinder 
engines.  It  consists  of  a  small  wheel,  which  is  mounted  on  the 
engine  shaft  opposite  the  flywheel,  and  two  weight  arms  whose 
centrifugal  effort  is  resisted  by  the  tension  springs  shown. 
Through  the  agency  of  two  links  the  arms  are  connected  to  the 
cam  sleeve.  This  sleeve  is  mounted  on  the  engine  shaft,  about 
which  it  is  free  to  move  under  control  of  the  weights.  The  cam, 
which  is  a  part  of  the  sleeve,  controls  the  opening  and  closure  of 
the  injection  pump  suction  valve.  The  governor,  as  shown,  is 
for  an  engine  running  anti-clockwise,  as  seen  when  facing  the 
governor  side  of  the  engine. 


Driven  by  movable  Cam  ft  Overflow  Porf  for 

°r  Cranhshaff  _j^.  ADJUSTING  }    Leakage 


FIG.  299. — Fairbanks-Morse  fuel  pump.     Section  through  plunger  and  suction 

valve. 

To  obtain  a  clear  understanding  of  the  action  of  the  governor, 
it  must  be  considered  in  conjunction  with  the  action  of  the  fuel 
pump.  Figures  298  and  299  show  views  of  the  pump  for  a  three- 
cylinder  engine. 

The  fuel  pump  plunger  C  is  driven  by  the  cam  A.  This  cam 
is  clamped  to  the  engine  shaft  as  outlined  in  Fig.  297^4.  This 
cam,  which  has  its  nose  or  lifting  surface  extending  over  about  15 
degrees,  strikes  the  roller  B,  which  is  mounted  on  the  end  of  the 
pump  plunger.  This  movement,  extending  over  15  degrees, 
injects  the  fuel  charge  into  the  cylinder.  The  exact  point  of 
injection  is  shown  in  Fig.  300.  Just  before  the  pump  plunger 
begins  its  outward  or  discharge  stroke,  the  governor  cam,  which 
has  been  holding  the  pump  suction  valve  open,  presents  a  low 
surface  Y  and  the  suction  valve  closes.  After  the  engine  shaft 


378 


OIL  ENGINES 


has  revolved  sufficiently  to  allow  the  pump  to  complete  its  in- 
jection stroke,  the  governor  cam,  which  is  rotating  with  the  shaft, 
presents  its  high  surface  to  the  suction  valve  plunger.  This 
again  opens  the  valve,  enabling  the  pump  to  take  in  another  fuel 
charge.  The  positions  of  both  governor  and  pump  cams  are 
shown  in  Fig.  298.  This  view  shows  the  relative  position  of 
the  cams  at  the  beginning  of  injection. 

The  governor  action  is  as  follows:  If  the  engine  speeds  up, 
the  weight  arms,  due  to  the  increased  centrifugal  force,  move 
outward  to  a  new  position.  This  movement  of  the  governor 
arms  causes  the  governor  cam  to  shift  clockwise,  or  opposite  to 


FIG.  300. — Fairbanks-Morse  vertical  oil  engine  fuel  injection  timing. 

the  direction  of  rotation.  The-  consequence  of  this  shifting  of 
the  governor  cam  is  to  cause  the  low  surface  on  the  cam  to  move 
under  the  suction  valve  push-rod  E  at  a  later  position  of  the 
engine  crank,  that  is,  the  suction  valve  is  held  open  during  the 
first  part  of  plunger's  discharge.stroke.  The  pump  plunger  then 
actually  forces  a  part  of  the  fuel  charge  back  through  the  open 
suction  valve  before  it  is  closed.  When  the  low  surface  on  the 
governor  cam  comes  under  the  suction  valve  plunger,  the  valve 
closes,  and  the  remainder  of  the  fuel  charge  is  forced  through 
the  discharge  valve  into  the  cylinder. 

It  follows  that  the  injection  point  of  the  engine  varies  with  the 
load.     The  change  from  no  load  to  full  load  is  not  great,  and 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      379 

no  objectionable  results  occur  when  oils  below  38°  Baume  are 
used.  It  is  always  advisable  to  have  the  -pump  injection  cam 
timing,  and  the  governor  cam  timing  as  well,  adjusted  to  suit 
the  particular  fuel  used.  Where  heavy  crude  under  24°  is  used, 
the  injection  angle  of  45  degrees  is  not  sufficiently  early  to 
insure  complete  combustion.  It  then  becomes  good  engineering 
for  the  operator  to  set  the  injection  at  an  earlier  point.  This  is 
by  no  means  beyond  the  powers  of  the  intelligent  engineer,  and 
this  adjustment  should  be  made  when  the  combustion  is  not 
good.  This  is  especially  true  where  the  engine  is  operated  con- 
stantly, for  a  10  to  15  per  cent,  fuel  saving,  which  may  result,  is 
attractive. 

When  the  engine  is  tested  out  at  the  factory,  the  cam  and  shaft 
are  marked.  This  marking  represents  the  proper  timing  for 
usual  conditions.  If  it  is  desired  to  have  the  injection  occur 
earlier,  the  pump  cam  should  be  undamped  and  shifted,  in  the 
direction  of  the  engine's  rotation,  the  desired  number  of  degrees. 
The  governor  should  now  be  shifted  a  corresponding  amount. 
Since  the  governor,  when  the  engine  is  at  rest,  holds  the  governor 
cam  in  a  position  slightly  more  advanced  than  when  under  operat- 
ing conditions,  to  reset  the  governor  to  conform  to  the  new  pump 
cam  timing,  it  should  be  shifted  until  the  leading  high  cam  point 
is  35  degrees  ahead  of  the  high  cam  point  of  the  pump  cam.  To 
shift  the  governor,  it  is  necessary  to  unclamp  the  bolts  and  use 
a  wedge  to  open  the  split  in  the  hub.  If  the  adjustment  of  the 
pump  cam  is  to  be  but  slight,  the  engineer  is  not  justified  in 
altering  the  governor  setting.  Loosening  up  the  governor  spring 
tension  will  cause  the  governor  to  shift  its  cam  enough  to  bring 
the  two  cams  into  proper  relationship.  These  springs  can  be  ad- 
justed until  the  correct  speed  is  obtained.  If  kerosene  or  very 
light  distillate  is  to  be  used,  the  timing  should  be  made  later.  In 
fact,  with  kerosene  20  degrees  ahead  of  dead-center  is  ample  for 
the  injection  point.  This  allows  all  the  fuel  to  enter  the  cylinder 
before  dead-center  is  reached. 

In  event  the  pump  refuses  to  deliver  oil  to  the  cylinder,  the 
pump  cam  should  be  inspected.  It  is  split,  being  held  by  a 
clamp  bolt,  and  is  liable  to  slip.  The  hammer  blow  due  to  the 
sudden  movement  of  the  pump  plunger  causes  the  plunger  roller 
to  chatter  against  the  cam  face,  leaving  a  series  of  ridges.  To 
eliminate  this,  the  builders  have  tried  an  inlay  of  tool  steel  at  the 
nose  or  high  point;  and  have  used  an  all  tool-steel  cam.  It  would 


380  OIL  ENGINES 

appear  that,  in  cam  construction,  the  cam  nose  only  should  be 
of  oil-treated,  high-carbon  steel,  while  the  body  of  the  cam  should 
be  of  cast  steel  or  machinery  steel  to  absorb  the  shocks. 

Adjustments  of  the  Fuel  Pump. — Attention  is  called  to  the 
starting  lever  M,  Fig.  298,  which  is  fulcrumed  on  the  pump 
housing  and,  in  starting,  is  used  to  pump  the  fuel  by  hand  to  one 
cylinder.  A  few  strokes  usually  fill  the  discharge  pipe.  When 
this  is  accomplished,  the  handle  is  set  to  the  neutral  position 
until  the  air  starter  is  cut  out.  In  stopping  a  multi-cylinder 
engine  the  by-passes  on  all  except  this  one  cylinder  is  opened, 
preventing  any  explosions  in  these  cylinders.  The  pump  handle 
is  then  slowly  drawn  back  so  that  the  fuel  to  this  one  cylinder 
is  gradually  reduced.  If  the  fuel  is  shut  off  instantaneously, 
the  engine  will  pound  very  violently. 

Another  important  detail  is  the  by-pass  valve  N.  Usually, 
in  starting,  the  engine  has  a  tendency  to  take  too  heavy  fuel 
charges  because  the  governor  arms  are  at  their  innermost  position 
and  the  movable  cam  at  its  most  advanced  point  so  that  all  the 
fuel  entering  the  pump  chamber  must  pass  through  the  discharge 
valve  into  the  cylinder.  To  overcome  this  objection,  the  by-pass 
valve  N  is  provided.  In  starting,  the  operator  opens  the  valve  a 
slight  amount,  thus  allowing  part  of  the  charge  to  flow  back  into 
the  suction  line.  Under  ordinary  conditions,  when  the  engine 
runs  only  partially  loaded,  it  is  advisable  to  " crack"  the  valve 
and  by-pass  part  of  the  fuel.  This  causes  the  governor  to  advance 
the  suction  valve  cam  so  that  the  charge  is  forced  into  the  cylinder 
earlier  than  when  the  by-pass  is  not  used  on  low  loads.  The 
result  is  a  greater  time  interval  for  the  fuel  to  vaporize  and  burn, 
and  better  combustion  is  obtained.  Where  the  engine  is  a  multi- 
cylinder  one,  adjusting  the  by-pass  valve  serves  to  equalize  the 
fuel  charges  to  the  different  cylinders.  It  is  impossible  to  secure 
exact  distribution  by  adjustment  of  the  suction  valve  tappet  rods. 

The  suction  valve  and  discharge  valve  are  of  the  spring-loaded, 
poppet  type,  and  in  regrinding  the  utmost  care  must  be  exercised. 
It  is  unnecessary  to  grind  the  valve  so  that  the  entire  seat  is  in 
perfect  contact.  A  line  contact  ^4  inch  in  width  is  very  satis- 
factory and  will  usually  be  better  than  a  poor  job  of  grinding  the 
entire  seat  into  contact.  While  the  erecting  engineer  may  in- 
struct the  operator  to  use  powdered  glass  as  the  grinding  medium, 
a  fine  grade  of  emery  flour  and  oil  has  made  an  excellent  job  on 
numerous  occasions. 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      381 

When  heavy  fuel  or  boiler  oil  is  used  unfiltered,  the  grit  carried 
with  the  oil  will  cut  the  pump  valves  rather  rapidly,  even  though 
the  engine,  at  all  times,  employs  a  small  oil  filter,  which  is  located 
immediately  above  the  pump.  Ordinarily,  such  oil  is  thick 
enough  to  be  sluggish  about  leaking  past  the  valves.  However, 
if  a  change  is  made  to  an  oil  of  lighter  gravity,  such  as  distillate 
oil,  the  valves  will  leak  badly,  since  this  oil  will  seep  by  a  valve 
showing  the  slightest  ridge  or  rough  spot  on  its  face.  If,  after 
making  a  change  in  the  oil,  the  engine  seems  to  lose  power,  the 
new  oil  should  not  be  the  subject  of  censure,  but  the  condition  of 
the  pump  valves  should  be  investigated.  This,  of  course,  applies 
to  any  and  all  makes  of  fuel  pumps. 


FIG.  301. — Governor  of  the  Mietz  and  Weiss  oil  engine. 

If  the  engine  is  of  fair  size — above  100  h.p. — and  tthe  flower 
cost  of  the  unfiltered  fuel  oil  is  attractive,  the  operator  should 
prepare  to  meet  these  valve  leaks.  It  is  a  good  plan  to  procure 
a  valve-seat  reamer  so  that  the  seat  may  be  brought  back  to  its 
proper  shape  when  badly  scored.  Since  the  valve  seat  is  of  brass, 
a  reamer  of  ordinary  tool  steel,  hardened,  will  do  good  work.  The 
reamer  should  be  in  the  shape  of  a  cone  with  a  number  of  cutting 
edges  or  notches,  and  the  sides  of  the  cone  should  have  a  45- 
degree  slope  to  conform  to  the  angle  of  the  valve  seat. 

After  regrinding  or  reaming  a  valve  seat,  it  is  imperative  that 
the  outer  end  of  the  valve  plunger  or  tappet  rod  be  adjusted  to 
give  the  proper  clearance  between  valve  stem  and  tappet  rod. 

Mietz  and  Weiss  Governor.— Figure  301  outlines  the  governor  of 
the  single-  and  two-cylinder  horizontal  Mietz  and  Weiss  oil  engines. 
The  governor  consists  of  a  weight  arm  A,  which  is  pivoted  to  the 


382 


OIL  ENGINES 


flywheel  by  the  pin  B.  This  arm,  by  means  of  a  pin  connection 
D,  moves  the  eccentric  along  the  governor  slide,  which  is  fastened 
to  the  crankshaft.  As  the  engine  speeds  up,  the  weight  arm 
tends  to  fly  outward,  moving  the  eccentric  along  the  governor 
block.  This  shortens  the  throw  of  the  eccentric,  which  in  turn 
reduces  the  pump  plunger  stroke.  In  order  to  secure  stability 
of  the  arm,  the  centrifugal  force  is  opposed  by  the  tension  in  the 
governor  spring.  This  method  of  changing  the  eccentricity  by 
means  of  the  sliding  governor  block  is  somewhat  similar  to  the 


Oil  Suction  Pipe 
Oil  Discharge  Pipe  \ 


Oil  Discharge  Pipe 
to  Second  Cylinder 


FIG.  302.' — Horizontal  twin-cylinder  oil  engines. 

Muncie  governor,  and  the  same  results  are  achieved —  variations 
in  both  pump  stroke  and  injection  angle,  or  angle  of  advance. 

The  principal  points  requiring  attention  are  the  condition  of  the 
slide  block  C  and  the  weight  pivot  pin  D.  This  pin  is  fitted  into 
the  weight  arm  bushing,  and  the  side  pressure  will  eventually 
wear  the  hole  oblong.  The  only  remedy  is  a  new  bushing.  The 
operator  should  in  no  event  neglect  the  pivot  oiler.  If  this  clogs 
up,  the  pin  wear  will  be  excessive  and  the  governor  will  be  sluggish 
in  action.  As  in  all  governors,  the  pins  will  in  time  wear  out  and 
should  be  renewed  when  there  is  any  excessive  side  play  in  the 
parts. 

Mietz  and  Weiss  Fuel  Pump. — The  fuel  pump  used  with  the 
governor  just  outlined  is  shown  in  Fig.  302.  This  particular 
pump  is  for  a  two-cylinder  engine;  the  single-cylinder  engine's 
pump  consists,  in  all  respects,  of  one-half  of  the  pump  shown. 


GO  VERNORS,  F  UEL  P  UMPS,  INJEC  TION  NOZZLES      383 

The  governor  eccentric  strap,  through  its  connection  with  the 
rocker  arm  E,  controls  the  pump  actuator  lever  F.  This  lever 
in  turn  gives  the  two  fuel  pump  plungers  G  a  travel  sufficient  to 
inject  the  required  amount  of  fuel  into  the  cylinder. 

The  actuator  used  on  the  horizontal  twin  engine  is  pivoted 
in  its  center.  The  pump  plungers  are  then  in  opposition.  The 
engine  cranks  are  180  degrees  apart,  and  the  actuator  causes  the 
pump  to  inject  the  oil  charges  into  the  two  cylinders  the  corre- 
sponding degrees  apart.  The  pump  is  provided  with  a  stroke 
regulator  which  allows  the  stroke  of  the  pump  to  be  altered  and 
the  speed  to  be  controlled  by  this  means,  however,  only  to  a 
minor  extent. 


Oil  Suction- 

c-; 

FIG.  303. — Governor  of  the  single  cylinder  Mietz-Weiss  vertical  engine. 

Mietz  and  Weiss  Vertical  Engine  Governor.— Figure  303  is  a 
cross-section  of  the  governor  and  pump  used  on  the  single-cylinder 
vertical  Mietz  and  Weiss  engine.  The  governor  is  of  the  flywheel 
type,  closely  following  the  lines  of  the  horizontal  engine  governor, 
while  the  pump  is  quite  similar  to  the  horizontal  engine  fuel  pump. 

Figure  304  is  a  cross-section  of  the  governor  and  pump  used 
on  the  Mietz  and  Weiss  vertical  multi-cylinder  engines.  The 
governor  is  mounted  on  a  shaft  which  is  driven  by  a  chain  belt 


384 


OIL  ENGINES 


from  a  sprocket  wheel  on  the  crankshaft,  the  gear  ratio  depending 
on  the  number  of  cylinders — as  example,  a  four-cylinder  unit  has 
a  ratio  of  1  to  4,  and  a  three-cylinder  engine  has  a  ratio  of  1  to  3. 
The  governor  consists  of  an  eccentric  C  fitted  with  two  weight 
arms  A  that  are  in  a  plane  at  a  slight  angle  with  the  plane  of  the 

horizontal  governor  shaft  D.  These 
arms  are  fitted  with  tension  springs. 
The  governor  shaft  passes  through  the 
eccentric  which  bears  on  a  milled  sur- 
face on  the  shaft  to  which  the  eccentric 
is  pinned  as  shown.  The  eccentric  strap 
fits  the  spherical  surface  of  the  eccentric 
and  drives  the  [pump  plunger  through 
the  linkage  outlined.  In  operation, 
when  the  load  decreases  the  engine 
speeds  up  slightly.  The  increased  cen- 
trifugal force  of  the  revolving  weight 
arms  overcomes  the  resistance  of  the 
springs,  and  the  weights  move  outward 
to  a  position  where  the  additional  tension 
of  the  springs  counteracts  the  effect 
of  the  increased  centrifugal  force.  The 
movement  of  the  arms  causes  the  eccen- 
tric, which  is  pinned  to  the  shaft  at  a 
point  outside  of  the  plane  passing 
through  the  center  of  the  spherical 
eccentric  and  perpendicular  to  the  shaft, 
to  shift.  This  produces  a  decreased 
eccentricity,  resulting  in  a  lessened 
pump  plunger  movement,  as  well  as 
altering  the  injection  angle. 

To  change  the  engine  speed,  it  is  only 
necessary  to  adjust  the  spring  tension. 
The  timing  of  the  oil  injection  can  be  changed  by  removing  the 
drive  chain  and  advancing  or  retarding  the  governor  sprocket 
wheel  the  desired  amount. 

Fuel  Pump  for  the  Mietz  and  Weiss  Vertical  Engines. — The 
fuel  pump  for  the  multi- cylinder  engines  is  incorporated  in  the 
governor  assembly.  It  consists  of  a  single  pump  block  with 
the  necessary  suction  and  discharge  valves  and  is  equipped  with 
one  plunger.  The  pump  is  further  provided  with  a  regulator 


FIG.  304. — Governor  of 
the  M.  &  W.  vertical  multi- 
ple cylinder  engines. 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      385 

lever.  This  lever,  through  a  wedge,  regulates  the  stroke  of  the 
pump,  in  addition  to  the  regulation  effected  by  the  governor. 
On  starting  the  engine,  the  regulator  should  be  adjusted  to  limit 
the  plunger  travel  to  a  low  value.  The  stroke  can  be  gradually 
increased  as  the  engine  comes  up  to  speed.  The  hand  regulation 
is  especially  desirable  when  the  engine  is  in  marine  service.  The 
regulator  is  also  of  use  in  advancing  or  retarding  the  injection 
angle  in  case  of  preignition  or  delayed  combustion. 

The  suction  and  discharge  valves  are  of  the  spring-loaded 
poppet  type.  For  regrinding,  pumice  flour  and  vaseline  make 
an  ideal  mixture.  The  valve  spring  should  be  removed  and  the 
valve  lightly  held  against  its  seat,  and  the  amount  of  grinding 
material  applied  should  be  very  meager.  If  a  thick  coat  of  the 
compound  is  placed  on  the  valve,  the  seat  will  be  cut  to  a  rounded 
form. 

The  Mietz  and  Weiss  Fuel  Pump  Distributor. — Since  the  fuel 
pump  for  the  multi-cylinder  engines  is  of  the  single-plunger  type, 
it  becomes  necessary  to  employ  some  mechanism  to  direct  the 
flow  of  oil  to  the  particular  cylinder  whose  crank  is  at  the  injection 
angle.  This  purpose  is  achieved  by  the  distributor,  as  shown  in 
Fig.  305.  This  consists  of  a  body  G,  gears  H,  and  distributing 
disk  /.  The  disk  is  driven  by  bevel  gears  from  the  governor-shaft 
and  has  an  oil  passage  through  it.  The  coverplate  /  of  the  dis- 
tributor is  further  provided  with  openings  from  which  the  oil 
lines  run  to  each  of  the  cylinder  nozzles. 

The  oil  from  the  injection  pump  is  forced  into  the  cavity  K 
below  the  disk.  From  this  chamber  it  flows  through  the  hole  in 
the  disk  and  enters  the  oil  line  whose  opening  registers  with  the 
disk  opening.  It  is  to  be  observed  that,  as  the  disk  rotates  in 
synchronism  with  the  engine,  its  port  successively  registers  with 
the  pipe  line  to  the  various  cylinders.  In  this  manner  the  oil  is 
injected  into  the  proper  cylinder.  The  disk  must  have  an  oil- 
tight  seat  on  the  distributor  cover.  If  a  leak  develops  here,  the 
oil  will  be  forced  into  the  cylinders  at  all  points  in  the  stroke. 
To  correct  any  cutting  or  uneven  wear,  the  cover  should  be 
removed  and  the  plate  and  cover  ground  together,  using  emenr 
paste.  It  requires  a  great  deal  of  care  to  prevent  the  plate  from 
being  ground  to  a  concave  surface.  Figure  306  shows  a  diagram- 
matical layout  of  the  oil  distribution. 

The  Mietz  and  Weiss  engine  operates  at  a  low  compression 
pressure,  about  90  pounds,  and  the  fuel  is  injected  very  early  in 

25 


386 


OIL  ENGINES 


OUTLETS  TO  CYLINDERS 

2  Outlet*  for  2  Cyl.  Eng.-  90°apart 

3  «        "3    "       "    -120°    " 


RATIO  OF 

GEARING. 

1.3forCyl.Eng 

1 .1  for  2  and  4. 

Cyl.  Eng. 


Outlets  A  and  D,  for  2  Cyl.  Eng. 
«       A,  B,  C      "3    "      «« 

««    A;D,  E,  F"  4  ««    «« 

FIG.  305. — Fuel  distributor  M.  &  W.  vertical  engines. 


ORDER   OF  ROTATION  OF  CRANK  PINS  SAME. 
AS  OIL  DISTRIBUTER  CONNECTIONS  1,  8,  2 


FIG.  306.— Mietz  and  Weiss  oil  engine.     Diagrammatical  layout   of  the  fuel 

distribution. 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      387 

the  compression  stroke.  Using  kerosene,  the  injection  can  begin 
as  late  as  45  degrees  ahead  of  rear  dead-center.  This  allows  the 
cut-off  at  full  load  to  occur  a  little  before  dead-center.  With 
heavier  oils  the  injection,  as  the  governor  is  usually  set,  begins 
when  the  piston  is  in  mid-position,  or  90  degrees  ahead  of  dead- 
center,  and  cut-off  occurs  at  approximately  45  degrees  before 
dead-center.  This  engine,  by  means  of  the  steam  and  water 
injection,  which  absorbs  much  heat  with  little  increase  in  tempera- 
ture, carries  a  low  compression  temperature.  Due  to  this  pecul- 
iar arrangement,  the  fuel  can  be  vaporized  very  early  in  the 
compression  stroke.  Even  though  the  oil  be  completely  vapor- 
ized and  mixed  with  the  air  charge,  the  temperature  does  not 
reach  the  ignition  point  until  the  piston  is  virtually  at  the 
end  of  the  stroke. 

Pump  Regulators. — It  will  be  noted  that  all  the  pumps  dis- 
cussed have  some  type  of  hand  regulator.  This  is  in  the  form 
of  a  lever  or  a  threaded  nut.  By  adjusting  the  regulator  the 
pump  plunger's  stroke  is  lengthened  or  shortened,  as  the  case 
may  be.  The  regulation  of  the  pump  stroke  affects  the  injection 
angle;  in  this  way,  by  proper  manipulation,  the  injection  angle 
can  be  altered  over  quite  a  range.  It  is  not  clear  to  many  engi- 
neers why  this  is  true.  While  it  is  generally  stated  that  the 
regulator  shortens  the  pump  stroke,  in  actual  operation  it  merely 
acts  as  a  stop  to  limit  the  return  or  suction  stroke  of  the  pump. 
The  pump,  on  the  power  stroke,  can  be  moved  as  far  as  the  throw 
of  the  eccentric  will  allow.  Thus  the  stroke  of  the  plunger 
is  limited  to  that  percentage  of  the  eccentric's  throw  which  lies 
between  its  point  of  contact  with  the  plunger  at  the  beginning  of 
the  power  and  its  extreme  point  of-throw.  The  argument  is  often 
advanced,  when  due  thought  has  not  been  given  to  the  subject, 
that,  if  the  return  travel  of  the  pump  is  shortened,  then  the 
eccentric,  in  order  to  maintain  speed,  will  increase  its  throw. 
This  increased  throw,  so  it  is  claimed,  will  increase  the  pump 
plunger  travel  sufficiently  to  enable  the  correct  amount  of  oil 
to  enter  the  cylinder.  Then,  the  argument  continues,  the  events 
are  back  to  the  original  state,  and  no  change  is  made  in  pump 
stroke  or  angle  of  injection  admission. 

To  correct  this  erroneous  belief,  attention  is  invited  to  Fig. 
307.  The  circle  E  with  its  center  at  A  represents  the  engine 
eccentric.  The  crank  is  represented  by  the  line  OF,  which  shows 
the  position  of  the  crank  when  the  eccentric  rod  strikes  the  pump 


388 


OIL  ENGINES 


plunger,  beginning  the  fuel  injection.  The  pump  stroke  then  is 
the  distance  $,  starting  at  the  point  F,  a  degrees  from  dead-center 
and  continuing  to  R,  which  is  at  dead-center.  It  is,  of  course, 
understood  that  the  end  of  injection  need  not  be  dead-center. 
It  may  be  at  any  angle  with  dead-center  dependent  on  the  angle 
which  the  line  of  shaft  and  eccentric  centers  made  with  the  crank. 
In  the  diagram  shown  this  angle  is  zero;  consequently  the  end 
of  injection  is  at  dead-center. 


FIG.  307. — Fuel  timing  control. 


Reverting  to  the  action  of  the  pump,  if  the  regulator  be  ad- 
justed to  stop  the  plunger  on  its  return  stroke  at  P',  then  the 
eccentric  will  strike  the  plunger  when  the  crank  is  along  the  line 
OH ,  a  degrees  ahead  of  dead-center.  The  total  pump  stroke 
would  then  be  P'R.  This  is  not  enough  to  keep  the  engine  up  to 
speed.  The  eccentric  increases  its  throw  with  its  center  at  A'. 
The  eccentric  then  strikes  the  plunger  at  G,  ft  degrees  from  dead- 
center,  continuing  to  inject  oil  until  dead-center  at  R'  is  reached. 
The  total  pump  stroke  S'  equals  S,  the  original  plunger  travel. 
It  is  evident,  then,  from  the  diagram  that  the  point  of  beginning 
of  injection  occurs  later  in  the  compression  stroke. 

It  follows  that  the  regulator  may  be  used  to  advance  or  re- 
tard the  point  of  admission.  If  the  fuel  be  light  and  displays  a 
proneness  to  preignite,  the  regulator  can  reduce  the  pump  stroke. 
The  eccentricity  increases  as  a  result  of  the  slight  decrease  in 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      389 

speed,  and,  while  the  pump  stroke  is  now  the  same  as  before,  the 
injection  is  later.  This  will  assist  in  reducing  the  preignition. 
The  reversal  of  this  action  may  be  used  if  the  oil  is  very  heavy,  re- 
quiring a  longer  time  for  vaporization.  This  manual  adjustment 
cannot  well  be  used  to  prevent  preignitions  which  occur  with 
varying  load  conditions,  since  it  would  require  constant  attention 
from  the  operator. 


FIG.  308. — Schematical  layout  of  the  Little  Giant  governor  and  fuel    pump. 

Little  Giant  Engine  Governor. — Figure  308  outlines  schematic- 
ally the  governor  used  on  the  Little  Giant  engine.  The  gov- 
ernor sleeve  A  is  connected  by  a  system  of  links  to  a  cam  B  that 
bears  against  a  collar  C  on  the  pump  plunger  D.  The  eccentric  is 
keyed  to  the  engine  shaft  and  moves  the  pump  plunger  through  a 
reach-rod,  not  shown.  Any  movement  of  the  cam  will  allow 
the  plunger  to  take  a  longer  or  shorter  suction  stroke,  as  the  case 
may  be,  and  thus  will  regulate  the  amount  of  oil  injected  into  the 
cylinder. 

The  spring-loaded  governor  is  belted  to  the  crankshaft,  and 
any  movement  of  the  balls  is  communicated  to  the  cam.  It 
is  apparent  that  each  variation  in  the  return  stroke  of  the  pump 
plunger  through  a  movement  of  the  cam  causes  the  injection 
angle  to  change.  Since  the  eccentric  is  keyed  to  the  shaft,  the 
crank  turns  until  the  eccentric  push-rod  strikes  the  pump  plunger. 
If  the  plunger  has  had  a  short  return  stroke,  then  the  crank  must 


390 


OIL  ENGINES 


turn  through  a  greater  angle  before  the  eccentric  rod  comes  into 
contact.  Unlike  the  pumps  previously  discussed,  there  is  no 
way  to  change  the  injection  angle  other  than  by  a  permanent 
shifting  of  the  fixed  eccentric.  All  preignitions  must  be  con- 
trolled by  means  of  the  water  injection. 

Little  Giant  Fuel  Pump. — Figure  309  shows  the  pump  used  in 
conjunction  with  the  above  governor.     It  is  a  very  simple  casting 


^'OUTLET 


FIG.  309. — Little  Giant  fuel  pump. 

and  is  provided  with  ball  valves,  both  for  the  suction  and  for  the 
discharge  line.  It  will  be  noticed  that  each  line  is  fitted  with 
two  ball  valves.  This  is  unnecessary  since  leakage  is  evident 
only  when  both  balls  fail;  consequently  one  may  leak  without 
detection,  bringing  conditions  back  to  the  use  of  a  single  ball. 
If  the  operator  runs  out  of  spare  valves,  the  pump  will  operate 
quite  successfully  with  one  set.  A  ball-bearing  ball,  which  can 
be  procured  at  any  garage,  makes  a  very  satisfactory  valve.  The 
governor  is  set  to  inject  the  oil  at  approximately  90  degrees  ahead 
of  dead-center. 

Governors  with  Constant  Injection  Angle. — A  governor  of  a 
design  that  will  maintain  a  constant  fuel  injection  point,  regard- 
less of  the  load  carried,  is  without  quest  ion  the  most  advantageous. 
Such  a  governor  will  relieve  the  engine  of  preignition  shocks, 
when  these  are  due  to  too  early  injection  and  not  to  poor  gas 
stratification.  In  an  engine  where  the  oil  is  vaporized  directly 
in  the  cylinder,  preignition  may  occur  practically  regardless  of 
the  injection  point.  The  vaporized  fuel  and  the  air  are  fairly 
well  mixed  as  soon  as  the  oil  is  sprayed  into  the  cylinder.  If 


GOVERNORS,  FUEL  P  UMPS,  INJECTION  NOZZLES      391 

the  temperature  existent  in  the  cylinder,  resulting  from  the  heat 
absorbed  from  the  previous  charge  as  well  as  from  the  compres- 
sion, is  high  enough,  the  charge  will  burn  considerably  before  the 
crank  reaches  dead-center;  in  fact,  preignition  has  occurred  when 
the  piston  is  at  mid-stroke.  On  the  other  hand,  if  the  fuel  is 
introduced  at  a  point  but  little  ahead  of  dead-center,  there  can 
be  no  preignition. 

With  governors  that  vary  the  angle  of  advance  with  the  load, 
there  is  no  danger  of  preignition  at  low  loads.  The  angle  of 
advance,  or  the  injection  angle,  at  low  loads  is  small,  and  the 
fuel  is  injected  but  little  ahead  of  dead-center.  On  heavy  loads, 
due  to  the  early  injection,  the  danger  of  preignition  is  consider- 
able. The  contrary  is  true  of  the  governor  with  a  fixed  injection 
point.  If  the  injection  point  be  such  as  to  preclude  preignition 
at  light  loads,  there  is  but  little  danger  of  full-load  prematures; 
however,  if  the  eccentric  is  so  set  as  to  cause  the  engine  to  pre- 
mature on  heavy  loads,  preignition  will  probably  occur  even  at 
light  loads.  The  statement  that  the  governor  with  a  fixed  in- 
jection point  is  the  better  in  operation  applies  only  where  a  com- 
bustion chamber  is  used.  In  this  construction  the  injection 
point  selected  must  be  a  favorable  one  for  full-load  conditions. 

One  source  of  criticism  is  the  thermal  loss  occasioned  in  this 
type  of  engine  at  low  load  factors.  Using  the  class  of  governors 
just  referred  to,  the  injection  point  must  be  placed  early  enough 
in  the  cycle  to  enable  all  the  fuel  required  at  full' load  to  be  in- 
jected before  dead-center  is  reached.  Indeed,  the  entire  fuel 
charge  must  be  injected  sufficiently  early  to  allow  it  to  be  com- 
pletely vaporized  by  the  time  the  piston  reaches  dead-center. 
It  follows,  then,  that  even  at  low  loads  the  fuel  is  introduced 
early  in  the  stroke.  This  oil,  on  vaporizing,  adds  to  the  existing 
pressure  in  the  cylinder  against  which  the  advancing  piston 
must  do  work  to  overcome  this  resistance.  This  work  is  not 
given  back  during  the  expansion  stroke  since  the  cooling  water 
has  partially  or  totally  absorbed  the  heat  produced  by  the  work 
performed  during  the  compression  stroke.  With  the  variable 
governor,  on  light  loads,  since  the  admission  is  later,  this  loss 
is  not  so  great.  Under  full-load  conditions,  the  losses  with  each 
type  are  equal. 

Another  disadvantage  lies  in  the  inability  of  the  engine  to 
carry  as  great  an  overload  as  is  possible  with  the  variable  injec- 
tion engine.  The  reason  for  this  is  that  the  builders  arrange  the 


392  OIL  ENGINES 

injection  point  to  allow  the  full-load  charge  to  be  injected  and 
vaporized  before  dead-center.  The  beginning  of  the  injection 
is  made  as  late  as  it  is  possible,  while  giving  a  sufficient  time  in- 
terval for  vaporization  before  dead-center.  The  result  is  that 
when  an  overload  is  experienced,  the  engine  cannot  obtain  enough 
vaporized  fuel  before  dead-center  to  enable  it  to  carry  this  addi- 
tional load.  If  such  an  engine  does  display  an  ability  to  handle 
a  large  overload,  it  naturally  follows  that  the  normal  injection 
point  is  too  early  for  economical  operation  at  partial  loads. 
Another  element  that  must  be  taken  into  consideration  is  the 
liability  of  preignition  with  early  injection,  but  this  can  be  con- 
trolled by  the  use  of  water  injection. 


FIG.  310. — Bessemer  oil  engine  governor. 

Bessemer  Oil  Engine  Governor. — The  governor  used  on  this 
engine  is  decidedly  novel  in  design.  The  governor  proper,  as 
shown  in  Fig.  310,  is  of  the  inertia  type,  the  governor  weight  being 
in  the  form  of  a  ring  A.  This  ring  is  pivoted  on  one  of  the  wheel 
arms  B,  and  its  movement  following  a  change  in  speed  is  opposed 
by  a  tension  spring  C.  The  eccentric  E  is  carried  on  an  arm 
which  is  pivoted  on  the  wheel  at  D  and  which  has  one  end  en- 
gaged in  a  slide  F  on  the  weight  circle.  The  eccentric  drives  the 
fuel  pump  through  an  eccentric  strap  and  reach-rod  G.  It  is 
evident  that  the  governor  circle  will  move  outward  when  the 
engine  speed  increases.  This  shifts  the  eccentric  E  toward  the 
shaft  center,  shortening  the  pump  stroke;  the  reverse  occurs  on 
an  increased  load  when  the  speed  drops. 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      393 

In  order  to  limit  the  movement  of  the  weight,  an  inner  and 
outer  stop  is  employed.  The  inner  stop,  which  is  the  one  ad- 
jacent to  the  tension  spring,  limits  the  movement  of  the  ring 
toward  the  spring.  This  stop,  then,  controls  the  maximum 
stroke  which  the  pump  plunger  can  take.  On  starting  the 
engine,  the  inertia  of  the  ring  causes  it  to  move  more  slowly  than 
the  wheel,  and  if  there  were  no  stop  the  pump  stroke  would 
be  excessive. 

To  prevent  the  eccentric,  at  an  increase  of  the  engine  speed, 
from  moving  across  the  shaft  center,  an  outer  stop  is  provided. 
This  is  adjusted  to  allow  the  eccentric  sheave  to  throw  central 
with  the  shaft  at  no  load.  This,  then,  is  the  minimum  position 
of  the  eccentric,  and,  being  central,  no  stroke  of  the  plunger 
occurs.  With  this  arrangement,  if  the  spring  breaks,  there  can 
be  no  run-away  since  the  eccentric  throw  would  be  reduced  to 
zero.  To  steady  the  governor  and  prevent  hunting,  a  dashpot  H 
is  supplied.  The  eccentric  rod  is  adjustable  but,  when  shipped, 
is  usually  regulated  to  give  the  proper  maximum  pump 
stroke. 

Bessemer  Fuel  Pump. — This  governor  is  used  in  conjunction 
with  the  fuel  pump  in  Fig.  312.  The  eccentric,  through  the 
agency  of  the  eccentric  rod,  actuates  the  pump  plunger  a.  The 

011  enters  the  pump  body  through  the  suction  opening  b  and 
the  suction  valve  F.     The  discharge  valve  is  spring-loaded  while 
the  suction  valve  F  is  mechanically  operated  by  means  of  a  bell- 
crank  N  and  rod  driven  by  the  cam  M,  Fig.  311,  which  is  keyed 
to  the  engine  shaft.     During  the  suction  stroke  of  the  pump  the 
suction  valve  is  held  open  by  the  bell-crank  N  and  cam  M.     When 
the  governor  reaches  its  dead-center  and  begins  its  return  or  deliv- 
ery stroke,  the  suction  valve  F  is  still  held  open.     The  oil  then 
merely  passes  back  through  the  suction  passage.     At  the  proper 
moment  the  flat  spot  0  on  the  cam  comes  under  the  cam  roller 
P.     This  allows  the  valve  plunger  spring,  Fig.  312,  to  force  the 
suction  valve  closed.     The  oil  raises  the  discharge  valve  and  enters 
the  cylinder  through  the  injection  nozzle.     After  the  crank  turns 

12  to  15  degrees,  the  roller  leaves  the  flat  surface  of  the  cam,  Fig. 
311,  and  the  suction  valve  is  reopened.     In  actual  operation  the 
suction  valve  is  not  open  longer  than  3  degrees.     This,  of  course, 
is  due  to  the  fact  that  the  tappet  does  not  completely  close  the 
valve  untiHhe  roller  has  traveled  several  degrees  on  the  flat  spot. 
This  valve-opening  action  prevents  any  further  injection  into  the 


394 


OIL  ENGINES 


FIG.  311. — Fuel  pump  suction  valve  control  cam. 


So.  3  Taper  Pin  after 

Post  is  Marte  Dp 

Tight  in  Place 


Auxiliary  Valve  Stem 

to  Project  not  less  than 

y£  nor  more  than  yj," 

above  Main  Valve 


Grind  Valve  Cage 

Seating  to  Perfect 

Fit         p 


Valve  to  have  not  less 
than  YM  nor  more 


Seat  must  be  Press  Fit 


FIG.  312. — Bessemer  oil  engine  fuel  pump. 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      395 

engine  cylinder.     The  cam  now  holds  the  suction  valve  open  for 
approximately  345  degrees. 

Figure  313  outlines  the  timing  and  the  crank  and  eccentric  posi- 
tion. The  flat  surface  of  the  cam  M,  which  is  keyed  to  the  shaft, 
covers  from  12  to  15  degrees,  dependent  on  the  engine  size.  When 
the  crank  C  is  in  the  position  shown,  37} £  degrees  from  dead-center, 
the  roller  P  moves  the  distance  shown.  The  eccentric  is  now  8 
degrees  from  mid-stroke.  The  eccentric  is  set  at  full  load  60 


FIG.  3 13. -T— Bessemer  oil  engine  pump  timing. 

degrees  behind  the  crank.  It  will  be  clear  from  this  diagram  that 
the  pump  eccentric  R  begins  its  return  or  discharge  stroke  at  a 
slight  angle  ahead  of  the  front  dead-center  S,  namely  22  degrees. 
The  discharge  stroke  continues,  regardless  of  the  length  of  the 
stroke,  throughout  180  degrees  of  revolution.  The  suction  stroke 
continues  for  the  other  180  degrees.  It  naturally  follows,  then, 
that  the  quantity  of  fuel  entering  and  leaving  the  pump  is  in 
direct  proportion  to  the  eccentricity.  On  light  loads  the  throw  is 
small,  and  the  pump  stroke  is  also  a  minimum,  resulting  in  a  mini- 
mum quantity  of  fuel  entering  and  leaving  the  pump;  on  heavy 
loads  the  amount  is  a  maximum.  Then  the  amount  of  fuel  per 


396  OIL  ENGINES 

degree  of  revolution  of  the  engine  varies  with  the  eccentricity. 
Consequently,  taking  any  small  segment,  such  as  the  length  of 
the  flat  on  the  cam,  de,  the  amount  of  fuel  that  is  pumped  while 
the  angle  is  being  covered  depends  on  the  throw  of  the  governor 
eccentric.  The  eccentric  is  so  placed  that  the  speed  of  the  pump 
is  at  its  maximum  value  when  the  cam  flat  0  closes  the  suction 
valve  F.  It  is  apparent  that,  with  this  design  of  governor  and 
fuel  pump,  the  commencement  and  completion  of  the  fuel  in- 
jection into  the  cylinder  are  constant  at  all  loads.  The  only 
variables  are  the  rate  of  travel  of  the  fuel  pump  plunger  per  degree 
of  engine  revolution  and  the  consequent  rate  of  oil  flow  per  de- 
gree of  revolution. 

From  this  discussion  it  is  obvious  that  the  velocity  of  the  oil 
jet  issuing  from  the  injection  nozzle  varies  with  the  load.  This 
probably  accounts  for  the  better  full-load  combustion,  since  the 
oil  atomization  is  nearer  perfect  at  a  high  jet  velocity.  The  op- 
erator is  seldom  called  upon  to  alter  the  setting  of  the  cam. 
While  it  is  keyed  to  the  engine  shaft,  if  an  adjustment  is  decided 
upon,  an  offset  key  can  be  used  to  hold  the  cam  in  its  new  posi- 
tion. A  slight  alteration  in  the  timing  of  the  suction  valve  may 
be  obtained  by  adjustment  of  the  tappet  /.  This  is  a  rather 
delicate  procedure  as  a  matter  of  two  turns  of  the  screw  will  cause 
the  valve  to  remain  open  during  the  entire  cycle.  If  the  tappet 
is  adjusted  very  closely  to  the  plunger,  the  suction  valve  opens 
early  and  closes  late,  resulting  in  an  excessive  fuel  charge,  which 
will  be  indicated  by  a  smoky  exhaust  and,  at  times,  by  blowing 
of  the  relief  valve.  When  the  roller  is  in  the  center  of  the  flat 
surface  on  the  cam,  the  clearance  between  the  valve  plunger  / 
and  the  tappet  should  equal  the  thickness  of  a  piece  of  writing 
paper.  Having  this  clearance,  at  its  maximum  upward  travel, 
the  suction  valve  opens  considerably  before  the  end  of  the  flat 
has  been  reached  by  the  roller  and  closes  some  degrees  after  the 
roller  strikes  the  flat.  As  already  stated,  the  actual  valve  closure 
covers  from  2  to  3  degrees  although  the  cam  flat  is  from  12  to  15 
degrees  in  extent. 

Reverting  to  the  pump,  the  suction  valve  demands  a  certain 
amount  of  attention.  The  valve  is  closed  by  the  action  of  a 
strong  spring,  and  a  heavy  blow  is  occasioned  to  the  flat  valve 
seat.  This  in  time  will  wear.  To  correct  this  a  light  cut  should 
be  taken  from  the  valve  and  the  valve  seat.  The  adjustment 
should  be  finished  up  by  regrinding  with  emery  flour  and  vaseline. 


GOVERNORS,  FUELPUMPS,  INJECTION  NOZZLES      397 

In  later  built  Bessemer  engines  the  suction  valve  is  equipped 
with  a  small  auxiliary  valve.  This  is  opened  a  trifle  ahead  of 
the  main  valve,  thus  relieving  the  pressure  and  making  it  easy 
to  open  the  main  suction  valve.  In  the  closing  action  this  small 
valve  seats  first,  avoiding  any  wire-drawing  effect. 

With  double-cylinder  engines  two  of  these  pumps  are  used, 
both  suction  valves  being  driven  by  the  one  cam  rod  while  the 
two  plungers  are  controlled  by  the  single  eccentric  rod.  To 
give  the  proper  timing  to  the  two  suction  valves,  the  fixed  or 
suction  cam  has  two  flat  spots.  Both  valves  are  opened  and 
closed  twice  during  each  revolution.  With  each  valve,  one 
of  the  closures  occurs  when  the  pump  plunger  is  on  the  suction 
stroke,  and  so  no  oil  is  injected  during  this  particular  valve 
closure. 


FIG.  314. — Primm  oil  engine  governor. 

Primm  Oil  Engine  Governor. — This  governor  is  of  the  con- 
stant injection-angle  type  and  is  possessed  of  certain  unique 
details.  The  assembly  is  shown  in  Fig.  314.  The  governor  con- 
sists of  a  governor  hub  F,  which  has  a  flange  G  forming  the  back 
side  plate.  About  this  hub  is  fitted  the  eccentric  bushing  H. 
The  eccentric  7  has  guides  milled  on  its  inner  surface  as  a  support 
for  this  bushing.  To  the  eccentric  is  fitted  a  pin  J  which  acts  as 
a  crank  in  moving  the  eccentric.  The  enlarged  end  of  this  crank 


398 


OIL  ENGINES 


pin,  which  is  recessed  into  the  front  coverplate,  is  provided  with 
a  governor  weight  arm  A .  An  additional  weight  arm  is  pivoted 
to  a  dummy  pin  K,  which  does  not  come  into  action.  The  sec- 
ond weight  merely  balances  the  active  weight.  The  crank  pin  D 
is  equipped  with  a  small  pinion  which  engages  a  gear  mounted 
on  the  governor  hub. 

In  operation,  the  action  is  as  follows:  Any  increase  of  speed 
causes  both  the  weight  arms  to  move  outward.  Since  one  weight 
arm  is  fastened  to  the  pinion  D  which  is  part  of  the  eccentric 
crank,  already  mentioned,  the  weight  arm  and  crank  may  be 
regarded  as  one  lever  fulcrumed  at 'the  pinion  tooth  which  is  in 
mesh.  Then  the  outward  motion  of  the  weight  causes  the  crank 
to  move  inward,  carrying  the  eccentric  with  it,  thereby  reducing 


FIG.  315. — Primm  oil  engine  fuel  pump. 

the  eccentricity.  This  change  in  eccentric  throw  reduces  the 
fuel  pump  stroke.  With  the  usual  governor,  the  change  in  ec- 
centricity would  alter  the  injection  point.  To  maintain  this  in- 
jection point  at  a  fixed  value,  the  governor  crank  is  set  so  that  the 
eccentric  receives  an  angular  motion  as  well  as  a  movement  across 
the  shaft.  The  angular  motion  corrects  the  defect  of  changing 
injection  point,  keeping  it  at  a  fixed  value.  The  movement  of 
the  crank  produces  a  rolling  or  angular  motion  at  the  fulcrum 
tooth.  This  is  taken  care  of  by  the  pinion.-  The  pinion  teeth 
remain  in  mesh  at  all  points  of  the  governor  crank's  displacement. 
The  governor  is  bronze-bushed  throughout,  and  all  parts  are 
oiled  by  the  single  sight  oiler.  Beyond  renewing  the  bushings 
when  worn  and  seeing  that  the  governor  is  lubricated,  the  oper- 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      399 

ator  has  little  trouble  with  it.  The  teeth  in  gear  and  pinion  will 
wear  slightly  after  some  length  of  service.  This  has  but  little 
effect  since  the  change  in  the  admission  angle,  due  to  back  lash 
at  the  pinion,  is  very  slight. 

Primm  Injection  Pump. — This  pump  is  outlined  in  Fig.  315. 
The  body  of  the  pump  is  a  bronze  casting  mounted  in  a  cast-iron 
housing  or  support.  This  pump  is  fibrous  packed,  being  provided 
with  a  gland  and  a  screwed  stuffing-box  nut.  The  plunger  is 


FIG.  316. — De  La  Vergne  type  D.H.  oil  engine  governor  and  fuel  pump. 

positively  driven  by  the  eccentric  rod  and  is  equipped  with  a 
return  spring.  The  valves  are  rather  different  from  accepted 
oil  engine  designs.  It  is  claimed  that  the  flat  seats  facilitate  re- 
grinding.  Since  the  fuel  used  is  ordinarily  filtered,  the  danger  of 
grit  getting  under  the  valves  is  remote.  The  operator  should  give 
these  valves  attention,  for  it  requires  less  cutting  to  injure  flat 
valves  than  ball  or  bevel-seated  poppet  valves.  The  stuffing- 
box  should  be  repacked  every  few  months.  A  good  many 


400 


OIL  ENGINES 


operators  have  the  habit  of  pulling  a  new  ring  behind  the  old 
packing  when  a  leak  develops.  The  only  correct  method  of 
stopping  seeping  around  the  plunger  is  the  renewal  of  the  entire 
packing. 

De  La  Vergne  Governor  and  Fuel  Pump. — The  governor,  Fig. 
316,  used  on  the  D.H.  engine  is  the  De  La  Vergne  standard  fly- 
ball  type  and  is  driven  by  bevel  gears  from  the  cam  or  layshaft 
A.  The  governor  controls  the  engine  speed  by  regulation  of 
the  amount  of  oil  entering  the  combustion  chamber.  This  is 


FIG.  317. — De  La  Vergne  type  D.H.  engine  valve  timing. 

achieved  by  means  of  a  by-pass  valve  B.  The  fuel  pump  is 
driven  by  a  cam  C  on  the  layshaft.  The  pump  stroke  is  constant, 
handling  a  fixed  quantity  of  oil.  Connected  with 'the  discharge 
line  is  the  by-pass  valve  B.  This  valve  is  opened  and  closed  by 
means  of  a  push-rod  D  actuated  by  a  cam  on  the  layshaft.  The 
lever  which  opens  the  poppet  by-pass  valve  is  fulcrumed  on  a 
pin  which  is  linked  to  the  governor  collar  E.  It  is  evident  that, 
if  the  governor  balls  rise  and  lift  the  collar,  the  fulcrum  pin  will 
move  to  a  lower  position.  This  allows  the  reach-rod  lever  to 
touch  the  valve  stem  B  earlier  in  the  cycle.  Early  valve  opening 
causes  most  of  the  fuel  charge  to  by-pass  back  into  the  return 
line  F.  On  heavy  loads  the  action  is  the  reverse  of  the  above. 
This  governor,  then,  is  of  the  constant  injection  type.  The 
timing  of  the  injection  period  depends  on  the  load  on  the  engine; 


GOVERNORS,  FUEL  PUMPS,  INJECTION  NOZZLES      401 

Fig.  317  gives  the  valve  timing.     The  velocity  of  injection  is 
constant  at  all  loads;  the  atomization  is  as  successful  at  low  loads 


as  at  the  heavy  loads.     To  this  may  be  attributed  the  excellent 
fuel  economy  at  all  loads.     Since  the  slightest  movement  of  the 


402  OIL  ENGINES 

fulcrum  pin  affects  the  valve  opening,  a  small  amount  of  wear  will 
alter  the  fuel  consumption.  The  links  and  pins  must  be  replaced 
at  the  first  evidence  of  wear. 

Buckeye -Barrett  Oil  Engine  Governor. — This  engine  uses  a 
vertical  centrifugal  governor  which  is  driven  from  the  cam- 
shaft by  a  bevel  gear.  The  method  of  drive  is  shown  in  Fig.  275. 
The  mode  of  governing  is  by  the  shifting  of  the  fulcrum  point 
of  the  lever  controlling  a  by-pass  valve.  This  is  shown  in  Fig. 
318,  which  gives  a  cross-section  of  the  fuel  pump. 

Buckeye -Barrett  Fuel  Pump. — The  fuel  pump  consists  of  a 
plunger  cavity  together  with  the  suction  and  discharge  valves, 
and  the  by-pass  valve  A.  In  operation  the  pump  plunger  is 
driven  by  the  push-rod  B,  which,  in  turn,  receives  its  motion 
from  a  cam  formed  on  the  governor  gear  shaft;  see  Fig.  275. 
This  plunger,  as  it  moves  inward,  forces  the  oil  up  through  the 
discharge  valve  C  into  the  fuel  line  to  the  nozzle.  •  The  oil  is 
injected  through  the  nozzle  until  the  lever  D,  which  is  moved 
by  the  pump  plunger,  engages  the  stem  of  the  by-pass  valve. 
The  opening  of  this  by-pass  valve  relieves  the  pump  discharge  and 
thus  prevents  any  additional  amount  of  oil  from  reaching  the 
nozzle. 

If  the  load  becomes  lighter,  the  movement  of  the  governor 
weights  and  the  reach-rod  F  causes  the  fulcrum  to  move  outward. 
This  enables  the  lever  D  to  strike  the  by-pass  valve  stem  earlier, 
reducing  the  quantity  of  fuel  entering  the  nozzle.  The  fuel 
plunger  begins  the  injection  of  the  fuel  when  the  crank  is  approxi- 
mately 40  degrees  ahead  of  dead-center,  continuing  for  some  20 
degrees,  dependent  on  the  load  carried.  The  regulation  of  the 
fuel  injection  is  by  means  of  the  by-pass  valve  alone.  This  can 
be  made  to  open  at  any  desired  point  by  adjustment  of  the  stem 
end.  In  resetting  this,  the  governor  should  be  blocked  in  its 
greatest  outward  position.  The  engine  should  then  be  turned 
over  by  hand  and  the  valve  stem  adjusted  so  that  the  valve  is 
opened  as  soon  as  the  plunger  begins  its  discharge  stroke.  If 
it  is  desired  to  change  the  timing  of  the  injection,  it  is  possible 
to  shift  the  cam  gear  one  tooth,  which  will  cause  the  plunger  to 
move  earlier  or  later,  according  to  the  direction  in  which  the 
gear  was  shifted. 


CHAPTER  XXIII 


FUEL  NOZZLES.     WATER  INJECTION 

Fuel  Nozzles. — All  fuel  nozzles  used  on  low-compression  en- 
gines show  much  similarity  of  design.  Unlike  the  Diesel  nozzle, 
there  is  but  little  attempt  to  thoroughly  atomize  the  fuel  charge 
as  it  leaves  the  nozzle  tip.  The  chief  use,  apparently,  for  the 
nozzle  is  its  service  as  a  check  valve  to  cut  off  the  fuel  supply  as 
soon  as  the  pump  ceases  to  inject  the  charge.  Since  all  low- 
pressure  engines  actually  vaporize  the  fuel  before  it  is  consumed, 
it  is  not  absolutely  necessary  that  the  oil  be  atomized,  but  there 
is  no  doubt  that  the  vaporization  and  combustion  are  more  or 
less  dependent  on  the  degree  of  atomization. 

In  the  nozzle,  as  in  the  fuel  pump,  a  quick-closing  and  abso- 
lutely tight  valve  is  necessary.  Many  of  the  poor  economy 
records  of  this  type  of  oil  engine  are 
due  to  the  inefficient  nozzle  valves. 
Closing,  as  it  does,  during  an  infi- 
nitesimal fraction  of  a  second,  it 
requires  a  tight  valve  to  prevent 
some  drops  of  oil  from  leaking  past 
the  seat. 

Little  Giant  Oil  Engine  Nozzle.— 
Figure  319  is  a  cross-section  of  the 
nozzle  used  by  the  Chicago  Pneumatic 
Tool  Co.  In  this  nozzle  a  single  ball 
valve,  spring-loaded,  serves  as  the 

check  and  assists  in  giving  a  snappy  cut-off  to  the  fuel  charge  at 
the  moment  the  pump  reverses  its  stroke.  The  oil,  in  issuing 
around  the  ball  valve,  enters  the  nozzle-tip  passage  through  the 
small  opening  in  the  spring  guard.  No  effort  is  made  to  secure 
a  breaking  up  of  the  fuel  in  the  nozzle,  and  consequently  the 
charge  strikes  the  hot  plate  on  the  piston  in  a  fairly  solid  stream. 

A  ball  valve,  after  the  seat  is  but  slightly  cut,  will  leak  more 
rapidly  than  a  poppet  valve.  With  this  fact  in  mind  the  engineer 
should  frequently  check  the  valve's  condition.  To  do  this,  the 
nozzle  can  be  unscrewed  from  the  head.  It  should  then  be 
screwed  onto  the  oil  line  and  the  pump  given  a  few  sharp  strokes. 

403 


FIG.  319. — Little  giant 
engine  nozzle.  (Chicago. 
Pneumatic  Tool  Co.) 


404 


OIL  ENGINES 


If  the  valve  leaks,  the  oil  leaves  the  nozzle  without  any  decided 
pressure  behind  it,  and  the  cut-off  of  the  pump  is  not  evidenced 
by  an  instantaneous  cessation  of  the  oil  flow.  It  is  necessary 
that  the  nozzle  be  held  horizontal  to  enable  the  ball  valve  to 
rest  on  its  seat. 

Muncie  Oil  Engine  Fuel  Nozzle. — This  nozzle,  Fig.  320,  also 
makes  use  of  a  ball  valve.  The  ball  in  this  instance  is  provided 
with  a  spring-loaded  cage.  The  nozzle  is  screwed  into  the  top 
of  the  cylinder-head  casting  in  a  vertical  position.  In  operation, 
the  fuel  pump  injects  a  charge  of  oil  into  the  nozzle.  The  oil 


FIG.  320. — Muncie  fuel  nozzle. 

pressure  forces  the  ball  B  downward  against  the  resistance  of  the 
spring-loaded  cage  C.  The  oil  flows  around  the  ball  and  then 
through  the  side  ports  into  the  cage  which  has  a  central  cavity 
D.  The  oil,  as  it  leaves  the  cage,  is  forced  out  through  the  small 
nozzle  opening.  This  opening  is  approximately  ^2  mcn  m  di- 
ameter. As  soon  as  the  pump  reverses  its  stroke,  the  spring 
snaps  the  ball  against  its  seat.  While  the  entire  nozzle  is  filled 
with  oil  during  the  period  of  combustion  in  the  cylinder,  there 
is  but  a  small  amount  below  the  ball  valve.  This  small  quantity 
usually  drips  out  into  the  cylinder. 

When  the  oil  used  is  of  an  asphaltum  base,  the  spring  and  cage 
are  prone  to  carbonize,  destroying  their  effectiveness.  When  the 
.cage  is  free  and  in  proper  working  condition,  it  emits  a  sharp 
click  at  each  pump  injection.  This  " clicking"  can  be  heard  by 
placing  the  ear  against  the  nozzle's  outer  end.  If  no  rhythmic 
click  is  heard,  the  nozzle  should  be  taken  off  and  the  carbon 
deposits  removed  by  soaking  in  strong  lye.  The  nozzle  tip 
opening  often  cakes  up.  This  can  be  removed  with  a  sharpened 


FUEL  NOZZLES,  WATER  INJECTION  405 

darning  needle.  Care  should  be  exercised  that  the  opening  is  not 
enlarged  during  the  process  of  cleaning. 

If  the  ball  valve  leaks,  a  small  hardwood  stick  should  be  placed 
squarely  against  the  ball  and  given  a  sharp  blow  with  a  light 
hammer.  After  long  use,  the  cage  wears  until  its  clearance  is 
more  than  the  J«j2  inch  which  is  standard.  In  such  event  a  thin 
sheet-steel  washer  can  be  cut  and  placed  between  the  cage  and 
nozzle  tips. 

Fairbanks-Morse  Type  "Y"  Fuel  Nozzle. — In  this  nozzle,  a 
cross-section  of  which  appears  in  Fig.  321,  an  attempt  has  been 


GUIDE  PISTON 


FIG.  321. — Fairbanks-Morse  oil  engine  fuel  atomizer  nozzle.     . 

made  to  partially  atomize  the  fuel  before  it  passes  the  check 
valve  A .  The  valve  stem  B  has  a  series  of  spiral  grooves  milled 
in  its  surface.  The  stem  fits  the  nozzle  cavity  rather  snugly,  and 
the  oil  is  forced  to  flow  along  the  spiral  grooves.  This  causes  the 
oil  particles  to  separate,  and,  after  passing  the  valve,  the  nozzle- 
tip  opening  completes  the  breaking-up  of  the  oil  into  minute 
globules.  The  valve  is  closed  by  the  reaction  of  the  spring.  This 
spring  should  be  compressed  about  %  inch  when  being  assembled. 
This  will  give  the  proper  tension  to  the  spring.  While  this  nozzle 
does  break  up  the  oil  fairly  well,  the  operator  must  keep  the  spiral 
grooves  clean.  With  heavy  oil,  a  deposit  of  coke  will  settle  on 
the  grooves,  choking  up  the  action  of  the  nozzle.  In  regrinding 
the  valve  seat,  emery  flour,  or  pumice  flour,  and  vaseline  make 
an  ideal  grinding  compound.  The  nozzle  should  be  held  in  one 
hand,  while  the  fingers  of  the  other  hand  are  used  in  rotating  the 
valve.  The  tension  of  the  spring  should  be  partially  relieved  by 
pressing  inward  with  the  finger.  It  is  not  necessary  to  grind  the 
entire  valve  face  into  contact.  A  light  line  contact  is  just  as 
serviceable  and  much  easier  to  obtain.  With  this  nozzle,  as  with 
all  others,  a  spare  one  should  be  on  hand  so  that  the  used  nozzle 
can  be  removed  and  soaked  in  lye  or  kerosene  to  thoroughly  clean 
all  the  parts. 


406  OIL  ENGINES 

If  there  is  any  suspicion  that  the  valve  is  leaking,  the  cap  of 
the  combustion  chamber  should  be  removed.  The  engineer  can 
then  have  his  helper  operate  the  fuel  pump  by  hand.  The  oil 
should  jet  out  of  the  nozzle  tip  in  a  fine  stream  that  breaks  up 
before  it  reaches  the  combustion  chamber  walls.  If  the  stream 
of  oil  is  not  fine,  the  nozzle-tip  opening  is  too  large  and  should  be 
replaced  with  one  having  a  smaller  opening.  If  the  valve  leaks, 
the  stream  of  oil  does  not  cut  off  quickly.  The  nozzle  tip  has  two 
openings.  The  main  opening  C  is  along  the  axis  of  the  nozzle, 
while  a  smaller  passage  D  is  at  an  angle.  In  operation,  when  a 
heavy  oil  is  used,  the  temperature  of  the  combustion  chamber  is 
not  sufficient  to  ignite  the  fuel.  An  alloy  tube  is  inserted  in  the 
chamber  wall;  this  tube  retains  the  heat  much  better  than  the 
cast-iron  combustion  chamber.  As  the  oil  enters  the  tip,  part 
of  the  charge  flows  out  through  the  angular  passage  and  strikes 
the  hot  tube.  This  assists  in  the  ignition  of  the  main  oil  charge 
which  has  flowed  through  the  axial  passage.  If  the  fuel  be  of 
light  gravity,  all  of  it  will  flow  through  the  axial  passage  C  due 
to  its  low  resistance  and  to  the  high  resistance  of  the  angular  pas- 
sage. With  light  oils  little,  if  any,  strikes  the  hot  tube.  The 
nozzle  tip  has  a  groove  on  one  side  which  fits  a  dowel  pin  in  the 
combustion  chamber.  It  is  imperative  that  this  dowel  rests  in 
this  groove  to  enable  the  oil  jet  to  strike  the  hot  tube.  The 
nozzle  itself  is  turned  on  its  outer  surface  and  fits  very  snugly 
into  the  engine  casting.  It  is  a  good  plan  to  clean  out  the  cavity, 
into  which  it  is  secured,  to  remove  any  carbon  that  might  pre- 
vent a  good  bearing. 

Buckeye -Barrett  Oil  Engine  Fuel  Nozzle. — This  nozzle,  Fig. 
322,  employs  two  spring-loaded  check  valves.  The  lower  one 
A,  which  is  immediately  behind  the  atomizer  tip  B,  performs 
the  office  of '  cutting  off  the  oil  flow  and  breaking  up  the 
oil  stream;  this  " breaking-up "  is  assisted  by  the  spring 
washers  which  are  perforated  with  a  series  of  small  open- 
ings. The  upper  check  C  merely  assists  the  lower  check 
valve  in  sealing  the  oil  line  against  any  danger  of  back-firing 
from  the  cylinder.  With  any  type  of  nozzle  where  the  check 
leaks,  there  is  danger  of  explosions  in  the  fuel  line  caused  by  the 
gas  flame  in  the  engine  cylinder  traveling  up  through  the  nozzle. 
The  use  of  two  check  valves  serves  to  confine  any  combustion 
to  the  nozzle. 


FUEL  NOZZLES,  WATER  INJECTION 


407 


To  regrind  the  valves  the  nozzle  is  disassembled  at  the  joint  D. 
The  nozzle  tip  is  also  removed.  Taking  up  the  lower  half,  the 
valve  spring  guard  E  should  be  removed.  This  frees  the  spring 
and  allows  the  valve  to  drop 
down.  The  valve  face  can  then 
be  lightly  coated  with  the  grind- 
ing compound.  In  grinding  the 
valve,  a  small  screw-driver  can 
be  inserted  in  the  slot  in  the  end 
of  the  valve.  No  pressure  should 
be  exerted  against  the  valve,  or 
the  seat  will  score. 

In  regrinding  the  upper  check, 
the  spring  guard  must  be  un- 
screwed from  the  nozzle  body 
and  the  spring  removed.  A  pair 
of  tweezers  can  be  used  to  grasp 
the  valve  stem  for  the  purpose 
of  rotating  the  valve. 

The  nozzle  end  fits  against  a 
ground  shoulder  that  effectually 
prevents  any  hot  gas  from  sur- 
rounding the  nozzle  body.  As 
a  consequence  of  this  sealing, 
there  should  be  no  coking  in 
the  nozzle. 

Primm  Oil  Engine  FuelNozzle. 
—This  nozzle,  Fig.  323,  is  built 
along  standard  and  accepted 
principles  as  regards  tip  and 
check  valve.  The  method  of 
connecting  the  fuel  line  to  the 
nozzle  is  somewhat  different 
from  the  general  practice.  The 
Primm  makes  use  of  a  yoke 
connection  which  admits  the 
fuel  into  the  nozzle  at  one  side,  the  junction  being  a  ball  and 
socket  joint. 

In  removing  the  nozzle,  which  is  screwed  into  the  cylinder- 
head  casting,  if  care  is  not  used  there  is  a  liability  of  twisting 
the  nozzle — especially  so  if  a  long-handle  wrench  is  used,  The 


FIG.    322. — Fuel    nozzle,     Buckeye- 
Barrett  oil  engine. 


408 


OIL  ENGINES 


best  method  of  removal  is  to  run  kerosene  around  the  nozzle  to 
cut  away  the  rust.  Then  the  nozzle  should  be  given  a  few  sharp 
blows  with  a  copper  mallet.  This  will  effectually  " break"  the 
joint  and  allow  the  nozzle  to  be  unscrewed  with  a  small  wrench. 


FIG.  323. — Fuel  nozzle,  Primm  oil  engine.       FIG.  324. — Bessemer  oil  engine 

fuel  nozzle. 

Bessemer  Oil  Engine  Fuel  Nozzle. — Figure  324  is  a  cross- 
section  of  the  nozzle  used  with  the  Bessemer  engine.  In  this 
design  no  nozzle  tip  is  used.  The  oil,  as  it  leaves  the  nozzle,  is 
in  the  form  of  a  cone.  The  lift  of  the  valve  A  is  so  slight  as  to 
cause  the  cone  of  oil  to  be  of  infinitesimal  thickness.  In  assem- 


FIG.  325. — Fuel  nozzle  for  Mietz  &  Weiss  oil  engines. 

bling  the  nozzle,  the  valve  spring  should  be  compressed  %  inch. 
This  gives  the  spring  enough  tension  to  cause  the  valve  to 
have  a  very  snappy  action.  After  repeated  regrindings  the 
valve  may  seat  so  deeply  as  to  cause  a  shoulder  at  the  nozzle 
end.  This  shoulder  prevents  the  oil  from  issuing  in  a  cone  and 
must  be  removed.  To  do  this  the  nozzle  should  be  ground  on 
an  emery  wheel  until  the  shoulder  disappears. 

Mietz  and  Weiss  Oil  Engine  Fuel  Nozzle. — This  nozzle,  a 
cross-section  of  which  appears  in  Fig.  325,  makes  use  of  two  check 


FUEL  NOZZLES,  WATER  INJECTION  409 

valves  and  a  nozzle  tip.     The  method  of  regrinding  the  valves 
is  the  same  as  used  on  any  similar  nozzle. 

Care  of  Fuel  Nozzles. — The  successful  operation  of  a  low- 
pressure  oil  engine  depends,  to  a  great  extent,  on  the  action  of 
the  fuel  nozzle.  The  check  valves  must  not  leak  and  must  close 
and  open  rapidly. 

At  least  once  every  thirty  days,  if  the  engine  is  in  constant 
service,  the  nozzle  should  be  removed  and  cleaned.  Kerosene 
or  strong  lye  water  is  by  far  the  best  cleansing  agent  to  use.  The 
interior  of  the  nozzle  should  be  inspected  and  all  coke  or  carbon 
deposits  completely  removed. 

After  cleaning  the  nozzle,  it  should  be  connected  to  the  pump 
line,  although  not  inserted  into  the  cylinder,  with  the  tip  removed. 
Kerosene  should  be  supplied  to  the  pump,  and  a  pint  or  so  should 
be  forced  through  the  discharge  line  and  the  nozzle.  This  will 
cleanse  the  line  and  nozzle  of  any  small  particles  of  grit  or  dust. 
The  tip  should  then  be  screwed  into  the  nozzle. 

To  check  the  nozzle  valve  action,  the  pump  should  be  given 
several  vigorous  strokes  to  remove  all  air.  As  soon  as  the  pres- 
sure builds  up  in  the  line,  which  is  evidenced  by  the  "pull"  of 
the  pump  handle,  the  pump  should  be  given  a  few  short  quick 
strokes.  If  the  nozzle  valve  does  not  shut  off  the  oil,  or  if  the  tip 
drips  oil,  it  is  proof  that  the  valve  is  leaking. 

In  regrinding  the  valve,  as  already  mentioned,  a  paste  of  emery 
flour  and  vaseline  should  be  used.  A  sparing  amount  should  be 
placed  on  the  valve,  spreading  it  over  the  entire  valve  seat.  Turn 
the  valve,  while  grinding,  with  the  fingers  only,  or  with  a  light 
screw-driver.  To  avoid  forming  grooves  on  the  valve  face,  the 
valve  should  be  lifted  frequently  and  given  a  forward  and  back- 
ward motion,  never  completely  rotating  it. 

In  operation,  after  replacing  the  nozzle,  the  engine  occasionally 
refuses  to  fire.  This,  in  most  cases,  is  due  to  the  fuel  pump  and 
nozzle  being  air-bound.  To  relieve  this,  the  line  should  be  dis- 
connected at  the  nozzle  and  the  pump  worked  by  hand  until  a 
solid  stream  of  oil  appears.  The  nozzle  should  be  filled  with  kero- 
sene, which  should  be  poured  in  slowly  to  allow  the  air  to  be 
displaced. 

As  to  the  efficiency  of  the  nozzle,  much  depends  on  its  location 
in  the  cylinder  or  combustion-chamber  walls.  If  the  nozzle  is 
in  a  vertical  position,  opening  upward  into  the  cylinder,  prac- 
tically no  drops  of  oil  will  enter  the  cylinder  after  the  valve  cuts 


410  OIL  ENGINES 

off.  On  the  other  hand,  the  oil  remaining  in  the  nozzle  tip,  above 
the  valve,  will  tend  to  vaporize,  and,  if  it  is  a  heavy  oil,  it  will 
leave  a  tarry  residue  which  will  choke  up  the  tip.  If  the  nozzle 
opens  downward  into  the  cylinder,  it  will  clear  itself  of  all  excess 
oil,  resulting  in  a  fairly  open  nozzle  tip.  But  this  position  allows 
the  excess  oil  to  drip  into  the  cylinder.  If  the  pump  and  nozzle 
valves  leak,  oil  will  drip  during  the  entire  stroke.  When  placed 
horizontally  in  the  head  or  combustion-chamber  walls,  the  nozzle 
seems  to  give  the  best  results. 

Water  Injection. — Originally,  water  was  injected  into  the 
cylinder  for  the  purpose  of  preventing  preignition,  and  it  un- 
doubtedly accomplishes  this  object.  In  those  engines  in  which 
the  fuel  is  injected  early  in  the  compression  stroke,  the  use  of 
water  is  absolutely  imperative  to  keep  the  compression  pressure 
below  the  preignition  temperature.  In  the  early  days  of  low- 
pressure  engines,  if  the  compression  pressure  rose  above  60  pounds 
the  engine  would  wreck  itself  if  the  supply  of  water  was  cut 
off. 

With  more  modern  designs  of  this  engine  the  injection  of 
fuel  occurs  much  later;  in  some  engines  the  injection  is  almost 
at  dead-center.  In  these  engines  the  elimination  of  preignition  is 
but  a  secondary  result  of  the  use  of  water.  The  principal  use  of 
water  injection  is  the  control  of  the  temperature  of  the  hot  bulfc 
or  combustion  chamber. 

It  is  very  apparent  that  with  a  given  size  bulb'  the  total  amount 
of  heat  that  the  bulb  will  absorb  is  dependent  on  the  amount  of 
heat  it  will  radiate.  If  it  receives  more  heat  than  it  can  give 
up  to  the  cooling  jacket  and  the  outside  air,  then  it  will  show  an 
increase  in  temperature.  The  result  is  that  on  low  loads,  if  the 
bulb  is  of  a  size  suitable  for  full  load,  the  temperature  of  the  bulb 
becomes  so  low  as  to  preclude  successful  ignition  of  each  fuel 
charge.  If  the  bulb  be  designed  for  half -load  conditions,  at  full 
load  the  temperature  of  the  bulb  becomes  so  great  as  to  cause 
preignition  even  though  the  fuel  be  injected  as  late  as  20  degrees 
ahead  of  dead-center.  The  size  of  the  bulb  cannot  profitably 
be  altered  at  each  load  change,  and  water  injection  does  serve  to 
control  the  temperature  of  the  bulb.  By  designing  the  bulb 
to  be  of  ample  size  to  vaporize  the  fuel  at  low  loads  the  water 
can  absorb  the  excess  heat  developed  under  full-load  conditions. 

Figure  326  shows  an  indicator  card  where  the  water  injection 
was  cut  out.  This  reveals  a  very  marked  preignition  considerably 


FUEL  NOZZLES,  WATER  INJECTION  411 

before  dead-center.  Figure  327  is  a  card  from  an  engine  using 
water  injection.  Even  at  full  load  there  was  no  premature 
combustion;  in  fact,  the  explosion  occurred  slightly  after  dead- 
center  was  reached. 

Another  use  of  water  injection  is  in  the  control  of  the  varying 
ignition  temperature  of  different  oils.  Oils  show  marked  differ- 
ences in  the  temperature  at  which  auto-ignition  occurs.  If  the 
compression  pressure  is  one  suitable  for  a  heavy  oil,  a  change 
to  a  lighter  gravity  oil  necessitates  a  lowering  of  the  compression 
temperature.  If  the  change  be  a  permanent  one,  the  clearance 
volume  of  the  engine  could  be  altered,  but  the  most  successful 
method  is  the  use  of  water  injection  to  lower  the  temperature 
of  the  cylinder  during  the  compression  stroke. 


Scale  240  Ibs.  FIG.  327. 

FIG.    326. — Low-compression   engine, 
no  water  injection. 

A  few  low-pressure  oil  engines  do  not  use  water  injection,  thus 
proving  that  it  is  not  absolutely  necessary  for  the  prevention  of 
premature  explosions.  If  water  is  not  used,  it  follows  that  the 
oil  must  not  be  injected  early  in  the  compression  stroke;  35 
degrees  ahead  of  dead-center  is  as  early  as  is  feasible,  and  even 
at  this  late  injection  point  the  stratification  in  the  cylinder 
must  be  good  or  preignitions  will  occur  on  full  load.  From 
considerable  experience  with  these,  so-called,  "dry"  engines  it 
can  be  stated  that  they  will  display  a  tendency  to  preignite  if 
operated  at  full  load  for  a  number  of  hours  and,  if  operated  at  a 
low  load  factor,  will  likely  possess  the  fault  of  missing  explosions. 

Of  late  years,  due  to  certain  objectionable  features  of  water 
injection  and  a  hesitancy  of  acknowledging  that  it  is  used  to 
correct  defects  of  design,  other  claims  of  the  virtues  of  water 
injection  have  been  set  up.  Among  the  uses  of  water  injection, 
it  is  now  considered  to  assist  in  better  combustion  and  to  keep 
down  carbon  deposits. 

It  is  practically  impossible  to  establish  exactly  what  occurs 
in  the  engine  cylinder.  All  that  it  is  possible  to  prove  is  that, 


412  OIL  ENGINES 

under  conditions  such  as  are  presumed  to  exist  in  the  engine 
cylinder,  certain  events  will  take  place,  and  from  this  basis 
deduce  that  these  same  events  do  occur  in  the  engine. 

Crude  oil  or  petroleum  is  made  up  of  an  extremely  complex 
mixture  of  carbon  and  hydrogen,  known  as  hydrocarbon.  The 
chemical  composition  of  the  crude  oil  in  each  field  shows  different 
characteristics.  In  fact,  even  in  a  single  field  the  oil  from 
different  wells  may  belong  to  an  entirely  different  hydrocarbon 
series.  There  are  five  of  these  hydrocarbon  series  that  are 
usually  met  with.  They  are 

CnH2n+2  =  Paraffine  Series 
CnH2n      =  Ethylene  Series 
CnH2n_2  =  Napthalene  Series 
CnH2n_4  =  Terpene  Series 
CnH2n_6  =  Benzene  Series 

although  hydrocarbons  of  a  series  as  low  as  CnH2n_24  have  been 
encountered.  These  hydrocarbons  have  a  characteristic  that 
has  given  considerable  trouble  to  the  engine  builder.  They  are 
subject  to  what  is  known  as  " cracking,"  whereby  at  a  given 
temperature  the  hydrocarbon  will  break  up  into  a  more  simple 
compound.  As  example,  at  a  certain  temperature  the  paraffine 
series  Ci5H32  breaks  up  as  follows: 

C15H32  +  Heat  =  2C7Hi6  +  C. 

This  "cracking"  temperature  is  considerably  lower  than  the 
temper ture  of  auto-ignition. 

It  was  found  that,  when  such  an  oil  was  " cracked"  and  then 
burned  in  the  presence  of  water  vapor,  the  free  carbon  C  disap- 
peared, evidently  consumed  in  connection  with  the  water  vapor. 

The  explanation  of  this  phenomenon  is  as  follows:  The  free 
carbon  atom  will  not  unite  with  the  oxygen  of  the  air  except  at  a 
temperature  much  higher  than  that  existing  in  the  engine.  On 
the  other  hand,  the  cylinder  temperature,  during  combustion, 
is  sufficient  to  disassociate  the  hydrogen  and  oxygen  of  the  water. 
This  nascent  oxygen  will  unite  with  the  carbon  at  the  cylinder 
temperature.  We  have  then  the  following  reactions: 

(1)  C15H32  +  Heat  =  2C7H16  +  C. 

(2)  C7H13  +  702  =  7C02  +  8H2. 

(3)  2H2O  +  Heat  =  2H2  +  O2. 

(4)  C  +  O2  +  Heat  =  CO2. 

(5)  2H2  +  O2  =  2H2O. 


FUEL  NOZZLES,  WATER  INJECTION  413 

Reaction  No.  1  occurs  as  soon  as  the  oil  is  injected  and  before 
ignition  occurs,  and  is  the  " cracking"  process.  When  the  cylin- 
der temperature,  assisted  by  the  hot  bulb,  ignites  the  vaporized  oil, 
reaction  No.  2  takes  place.  The  temperature  which  now  exists 
in  the  cylinder  is  around  3000°  Fahrenheit,  sufficient  to  sepa- 
rate the  water  into  its  hydrogen  and  oxygen  atoms.  Conse- 
quently the  hydrogen  released  by  No.  2  reaction  does  not  unite 
with  the  oxygen  of  the  air.  As  already  stated,  this  water  oxygen 
will  unite  with  the  carbon  and  reaction  No.  4  occurs.  As  the 
piston  moves  outward,  the  temperature  falls  below  the  disassocia- 
tion  point  of  water,  and  the  hydrogen  set  free  by  No.  2  reaction 
unites  with  the  oxygen  freed  by  No.  3  reaction. 

This  would  seem  to  explain  the  reason  a  "dry"  engine  operates 
at  a  higher  temperature  than  does  a  water  injection  engine.  The 
reactions  absorb  considerable  heat,  which  is  of  course  given  up 
by  reaction  No.  5.  However,  this  last  reaction  occurs  when 
the  piston  is  fairly  well  advanced  on  the  power  stroke  and  the 
cylinder  temperature  at  this  point  is  low  enough  to  receive  an 
increment  without  overheating  the  engine. 

To  offset  this  claim  many  "dry"  engines  are  operating  at 
practically  full  load  with  no  carbon  deposits.  Even  water- 
inj  ection  engines  usually  operate  below  half  load  without  the  use 
of  any  water,  and  no  carbon  deposits  appear.  There  is  no  doubt 
that  water  injection  does  prevent  preignitions  at  full  load  and 
assists  in  clearing  the  cylinder  of  exhaust  gases.  This,  however, 
is  better  obtained  by  proper  design  of  the  air  ports. 

Cylinder  Wear  Due  to  Water  Injection. — It  has  frequently 
been  observed  that  engines  using  water  injection  are 'subject  to 
serious  cylinder  wear.  This  is  more  prevalent  in  the  Southwest 
where  the  oil  carries  considerable  sulphur.  This  sulphur  un- 
doubtedly does  unite,  to  some  extent,  with  the  water  introduced 
into  the  cylinder,  forming  sulphurous  acid.  This  acid  cuts  the 
cylinder  and  piston  walls.  From  reports  of  a  number  of 
engines  using  Eastern  oils  that  contain  little  or  no  sulphur  it 
appears  that  cylinder  wear  occurs  without  the  presence  of  sulphur. 
This  could  be  explained  on  the  grounds  that  the  oxygen  of  the 
water  unites  with  the  iron  of  the  walls,  forming  ferric  oxide.  This 
oxide  is  very  abrasive  and  cuts  the  walls,  presenting  a  fresh  iron 
surface  to  the  action  of  the  water. 

Faulty  Lubrication  Caused  by  Water  Injection. — The  opponents 
of  the  use  of  water  injection  claim,  with  some  degree  of  truth, 


414  OIL  ENGINES 

that  it  tends  to  wash  the  lubrication  off  the  piston  and  that  faulty 
lubrication  is  the  chief  cause  of  the  rapid  cylinder  wear.  From 
reports  obtained  it  would  appear  that  rapid  cylinder  wear  takes 
place  in  those  cases  where  the  operator  has  followed  shop  instruc- 
tions as  to  the  amount  of  lubricating  oil  to  use.  Since  the  engine 
builder  usually  states  the  minimum  amount  advisable  to  use 
under  the  best  conditions,  it  follows  that  the  operator,  in  limit- 
ing the  quantity  of  oil  to  this  figure,  did  not  use  enough.  The 
piston  and  cylinder  wear  rapidly  because  the  water  washes  away 
the  oil  that  is  supplied.  All  reports  on  cylinder  wear  make 
mention  of  the  dry  condition  of  the  piston,  showing  the  absence 
of  any  lubricant. 

The  Method  of  Water  Injection. — This  has  much  influence  on 
the  degree  of  cylinder  wear.  Figure  251  shows  a  cross-section 
of  an  engine  using  a  simple  bleeder  valve.  As  shown,  the  water 
connection  enters  the  cylinder,  although  the  majority  of  engines 
using  water  have  the  water  line  leading  into  the  air  passage. 
The  water  is  injected  solely  by  the  difference  between  the  pressure 
existing  in  the  engine  cooling  jacket  and  the  pressure  in  the 
cylinder  or  air  passage.  The  intention  of  the  designer  is  to 
cause  the  water  to  be  injected  at  the  moment  the  piston  uncovers 
the  exhaust  port,  the  cylinder  pressure  dropping  to  zero  at  this 
point.  If  the  water  entered  at  this  time,  the  heat  in  the  cylinder 
would  transform  it  into  steam  and  probably  no  cylinder  cutting 
would  occur.  It  happens  that  on  the  compression  stroke  the 
air  pressure  in  the  crankcase,  or  front  end  of  the  cylinder, 
drops  below  the  atmospheric  pressure.  The  pressure  difference 
will  cause  the  water  to  drip  into  the  cylinder,  or  air  passage,  and 
run  down  onto  the  piston.  This  will  evidently  wash  away  any 
oil  film.  With  an  automatic  pump  arrangement  the  water  is 
injected  at  a  fixed  point  when  the  piston  has  uncovered  the 
exhaust  and  air  ports.  The  existing  cylinder  temperature  is  suffi- 
ciently high  to  vaporize  the  water  into  steam.  Under  these 
conditions  there  should  be  but  little  effect  shown  on  the  piston 
lubrication. 

Mietz  and  Weiss  Water  Injection  System. — The  Mietz  and 
Weiss  horizontal  oil  engines  make  use  of  a  unique  design  of  water 
injection.  The  cylinder  water  jacket  is  provided  with  a  float 
box  A,  Fig.  328.  The  water  line  to  the  cylinder  jacket  is  con- 
nected through  the  float  box,  the  float  of  which  maintains  the 
water  in  the  jacket  at  a  level  about  two-thirds  from  the  top. 


FUEL  NOZZLES,  WATER  INJECTION 


415 


The  heat  in  the  cylinder  evaporates  this  water,  forming  it  into 
steam  at  atmospheric  pressure,  or  a  few  pounds  gage.  This 
steam  is  led  into  the  air  passage  through  the  steam  dome  B. 
When  the  pressure  in  the  air  passage  drops  below  the  pressure 
in  the  jacket,  there  is  a  flow  of  steam  into  the  air  passage  and  the 


145 


Wafer  SupplyhoEngine  from 
lank  of  Service  Pipe 


Muffler. 


The  Wafer  is  Evaporated  in  Jacket  of 
Cylinder  and  Used  in  Engine, 


FIG.  328a. 

engine  cylinder.  At  the  time  the  exhaust  port  opens  the  cylinder 
pressure  drops  to  atmospheric,  and  a  supply  of  steam  rushes 
in  with  the  air  charge.  This  assists  in  cleansing  the  cylinder  of 
the  exhaust  gases  and  also  serves  to  lower  the  compresssion 
temperature,  due  to  the  absorption  of  heat  by  the  steam,  which 
has  a  greater  specific  heat  capacity  than  has  air. 

To  provide  an  additional  cooling  agent  a  water  bleeder  valve 
is  also  used.     The  water  drips,  as  is  customary,  into  the  air  pas- 


416  OIL  ENGINES 

sage  and,  being  blown  into  the  cylinder,  assists  in  reducing  the 
temperature. 

The  one  objection  to  the  use  of  steam  is  the  tendency  for  it  to 
pass  into  the  crankcase  when  a  suction  pressure  exists  there,  thus 
partially  destroying  the  compressor  efficiency. 

The  arrangement  for  the  vertical  engines  is  somewhat  different. 
The  float  box  is  so  located  that  the  water  level  in  the  jacket  is 
several  inches  below  the  top  of  the  cylinder  head.  The  conse- 
quence is  that  on  full  load  the  head  runs  abnormally  hot.  In 
many  installations  of  vertical  engines  the  operator  has  abandoned 
the  boiler  idea  and  used  a  standard  circulating  water  system, 
depending  on  the  water  jet  for  internal  cooling  in  preference  to  the 
steam.  To  .do  this,  the  float  box  and  steam  dome  are  removed. 
The  entrance  to  the  air  passage  from  the  dome,  as  well  as  the  con- 
nection into  the  jacket  for  the  water  line  from  the  float  box,  is 
plugged  up.  The  water  is  put  into  the  jacket  through  passages 
at  the  bottom  which  are  ordinarily  plugged  and  are  used  for 
cleaning  purposes.  The  water  discharge  line  is  connected  to 
the  opening  that  previously  ran  to  the  steam  dome. 

With  water  carrying  mineral  salts  the  float  valve  tends  to 
scale,  destroying  its  regulating  powers.  To  remove  the  scale  is 
absolutely  necessary;  a  muriatic  acid  solution  left  in  the  float 
box  for  a  couple  of  hours  will  eliminate  this  deposit. 

Muncie  Oil  Engine  Water  Injection. — In  all  sizes  of  Muncie 
engines  the  standard  water  injection  system  consists  of  a  bleeder 
valve  between  the  jacket  and  the  air  passage,  as  outlined  in 
Fig.  251. 

Muncie  Automatic  Water  Pump. — In  the  larger  sizes  the 
Muncie  Co.  is  now  supplying  a  water  pump  that  is  incorporated 
in  the  design  of  the  fuel  injection  pump.  By  this  arrangement 
the  amount  of  water  injected  into  the  cylinder  is  under  control 
of  the  governor.  Figure  329  shows  their  latest  automatic  water 
pump,  the  lower  pump  being  that  used  for  the  water.  The 
eccentric  rod  B  on  the  return  stroke  of  the  fuel  pump  strikes  the 
lever  A,  which  in  turn  gives  a  stroke  to  the  water  pump  plunger 
C.  As  the  lever  A  forces  the  water  plunger  inward,  injecting  a 
charge  of  water  into  the  engine  cylinder,  it  engages  the  by-pass 
valve  stem  D.  The  opening  of  this  by-pass  valve  relieves  the 
water  discharge  line,  the  flow  of  water  to  the  injection  valve  then 
ceasing.  The  lug  E  allows  an  adjustment  of  the  timing  of  the 
by-pass  valve,  in  this  way  regulating  the  amount  of  water  which 


FUEL  NOZZLES,  WATER  INJECTION 


417 


enters  the  cylinder  for  a  given  movement  of  the  governor  eccen- 
tric rod.  When  heavy  oil  is  used  but  little  water  is  necessary, 
consequently  the  adjusting  nut  is  screwed  inward  on  the  valve 
stem.  This  causes  the  valve  to  open  practically  as  soon  as  the 
water  plunger  moves.  If  the  oil  is  light,  more  water  is  necessary 
so  the  by-pass  valve  is  allowed  to  remain  closed  until  the  water 
plunger  has  completed  the  major  portion  of  its  stroke.  It  will 
be  observed  that  the  adjustment  of  the  by-pass  valve  allows  the 


Water  Suction  Line  "*      Watei.Relief JJne 

FIG.  329. — Muncie  oil  engine,  fuel  and  water  injection  pump. 


necessary  water  to  be  used  for  any  certain  oil,  while  the  governor 
itself  regulates  the  quantity  admitted  on  the  various  load  charges. 
It  is  of  frequent  occurrence  that  the  engine  operates  better  when 
the  water  is  injected  at  some  fixed  point.  The  lug  screw  F  can 
be  adjusted  so  that  the  water  will  enter  the  cylinder  at  any  point 
between  the  point  of  exhaust  port  opening  and  exhaust  port 
closure.  When  heavy  oil  is  used,  early  water  injection  produces 
a  good  scavenging  effect.  With  light  oil,  inclined  to  preignition, 
early  water  admission  allows  most  of  the  water  vapor  to  blow 
out  the  exhaust,  consequently  the  cooling  effect  on  the  cylinder  is 
slight.  With  such  oils  late  water  injection  serves  to  keep  most  of 
the  water  in  the  cylinder,  thereby  providing  an  effective  cooling 
medium. 


27 


418 


OIL  ENGINES 


Primm  Oil  Engine  Water  Injection. — The  Power  Manufacturing 
Co.  makes  use  of  a  valve  A,  Fig.  330,  which  is  controlled  by  the 
governor.  The  valve,  itself,  consists  of  a  disk  with  a  series  of  holes 
registering  with  like  openings  in  the  valve  body.  The  valve  stem 
is  linked  to  the  fuel  pump  plunger  B,  and  the  degree  of  valve 
opening  is  dependent  on  the  length  of  the  pump  plunger  stroke. 
The  actual  quantity  of  water  passing  through  the  valve  at  maxi- 


FIG.  330. — Primm  oil  engine,  water  regulating  valve. 

mum  valve  opening  can  be  regulated  by  means  of  the  globe 
valve  shown.  In  later  models  the  Primm  water  valve  is  supplied 
with  a  regulating  needle  valve  in  place  of  the  globe  valve  C. 

Little  Giant  Oil  Engine  Water  Injection. — The  Chicago  Pneu- 
matic Tool  Co.,  on  their  Little  Giant  engine,  use  a  governor- 
controlled  bleeder  valve.  This  valve  is  connected  to  the  Pickering 
governor  by  a  link,  and  the  movement  of  the  governor  on  load 
changes  alters  the  valve  opening.  The  action  of  the  valve  itself 
is  subject  to  the  influences  that  act  on  a  manual-controlled  bleeder 
valve,  as  the  timing  of  the  water  inj  ection  is  not  positive. .  A  globe 
valve  is  used  to  give  the  proportion  of  water  to  fuel  charge  at  any 
given  load  value. 

Bessemer  Oil  Engine  Water  Injection  System. — The  Bessemer 
water  injection  is  controlled  by  a  water  pump  embodied  in  the 


FUEL  NOZZLES,  WATER  INJECTION  419 

fuel  pump  casting.  The  stroke  of  the  water  pump  is  under  direct 
control  of  the  engine  governor  through  a  floating  fulcrumed  lever. 
This  lever  is  adjustable,  enabling  the  operator  to  regulate  the 
amount  of  water  used  on  any  given  load.  The  governor  then 
automatically  controls  the  water  for  any  other  given  load,  pro- 
portioning the  water  injection  in  accordance  with  the  quantity 
of  fuel  injected. 

Engines  Without  Water  Injection. — As  has  been  mentioned 
heretofore,  a  number  of  engines,  such  as  the  Fairbanks-Morse 
and  the  De  La  Vergne,  operate  "dry,"  making  no  use  of  water 
injection  as  a  temperature  control  but  depending  on  the  water 
cooling  of  the  combustion  chamber  to  keep  the  temperature  of 
the  combustion  chamber  within  the  desirable  range.  Others  use 
a  simple  bleeder  valve. 

General. — If  an  engine  using  water  injection  is  to  be  purchased, 
automatic  control  of  the  water  should  be  insisted  upon.  All 
manufacturers  are  in  a  position  to  supply  the  automatic  control 
if  the  purchaser  makes  it  one  of  the  conditions  of  the  sale.  If 
an  engine  already  installed  has  a  manual-controlled  bleeder  valve, 
the  operator  should  early  decide  that  it  will  be  impossible  to  alter 
the  valve  setting  at  each  change  of  load.  The  proper  method  is 
to  adjust  the  valve  to  suit  average  load  conditions.  If  the  engine, 
momentarily,  has  a  heavier  load  to  handle,  the  operator  should 
allow  the  engine  to  pound  a  little ;  as  long  as  the  preignitions  are 
not  violent,  the  water  valve  should  not  be  touched.  If  the  load 
becomes  less  than  normal,  the  water  will  be  excessive  and  the 
engine  will  probably  miss  an  occasional  explosion.  This  miss- 
firing  should  be  allowed  to  occur  as  long  as  the  engine  does  not 
begin  to  "hunt."  The  operator  cannot  afford  to  spend  his  time 
in  adjusting  the  bleeder  valve  to  conform  to  every  load  change. 

Manipulations  of  the  Water  Injection. — On  starting  the  engine, 
the  water  valve  should  be  shut  off  entirely.  If  it  be  a  pump  feed, 
the  pump  should  have  its  stroke  reduced  to  the  minimum.  After 
the  engine  has  been  started  and  the  load  thrown  on,  the  water 
should  be  increased  until  all  premature  explosions  have  been 
subdued.  The  amount  of  water  supplied  should  never  be  so 
plentiful  as  to  unduly  chill  the  combustion  chamber  or  bulb. 
Usually  a  cold  bulb  is  evidenced  by  missed  explosions,  "hunting" 
of  the  engine  and  occasional  violent  preignitions  as  well  as  a 
liquid  exhaust. 


CHAPTER  XXIV 
EXHAUST  PIPE  AND  PIT.     WATER  COOLING   SYSTEMS 

Exhaust  Pipe. — In  planning  the  installation  of  a  low-pressure 
oil  engine,  the  exhaust  piping  should  be  made  as  short  and  direct 
as  possible.  All  elbows  that  are  not  absolutely  necessary  should 
be  eliminated.  In  a  horizontal  engine  plant  the  best  pipe  layout 
has  the  exhaust  pipe  running  straight  down  from  the  engine  to 
the  exhaust  elbow  which  rests  in  a  pipe  conduit.  The  exhaust 
pipe  should  run  from  the  elbow,  through  the  conduit,  into  the 
exhaust  pit,  located  outside  the  building.  The  pit  should  be  at 
least  3  feet  from  the  building  wall  to  avoid  lire  risk.  Good 


Lb 'as  to  hold 
--Bolt. 


FIG.  331. — Exhaust  elbow  with  clean  out  door. 

engineering  specifies  that  the  pipe  conduit  must  have  concrete 
walls  and  bottom  and  be  provided  with  a  cast-iron  cover,  al- 
though a  wooden  cover  will  do  in  an  emergency.  The  exhaust 
elbow  should,  if  possible,  be  of  special  design  with  a  clean-out 
door  at  the  back;  see  Fig.  331.  A  tee  instead  of  an  elbow  can  be 
used  with  one  outlet  closed  by  a  plug  or  blind  flange.  This  ad- 
mits of  cleaning  out  the  vertical  pipe.  Figure  332  shows  a  well- 
planned  pipe  layout.  If  the  conduit  be  extended  along  one  side 
of  the  engine  foundation,  the  oil  and  water  piping  can  also  be 
run  in  it,  out  of  the  way. 

The  majority  of  engine  builders  have  the  exhaust  pipe  sizes 
suitable  for  short  lines  only.  If  the  building  plan  necessitates  a 
longer  run,  the  pipe  should  be  increased  at  least  one  size.  In 

420 


EXHAUST  PIPE  AND  PIT 


421 


laying  the  pipe,  it  should  be  sloped  to  drain  away  from  the  engine. 
A  plugged  opening  should  be  drilled  in  each  exhaust  pipe  immedi- 


ately below  the  cylinder.  By  removing  the  plug,  the  operator 
can  tell  exactly  how  the  engine  is  firing  and  the  condition  of  the 
exhaust  gases. 


422  OIL  ENGINES 

A  common  practice  is  the  connection  of  two  engines  to  a  single 
exhaust  pit.  Each  engine  should  have  its  individual  exhaust 
pit  or  pot.  With  two-stroke-cycle  engines,  where  a  common 
exhaust  pit  is  used,  when  only  one  engine  is  in  operation  the 
exhaust  gases  will  back  up  the  second  pipe  and,  if  the  piston  is  at 
the  end  of  the  stroke,  enter  the  cylinder.  If  the  exhaust  is  the 
least  bit  smoky,  the  unburnt  carbon  will  settle  on  the  cold  cylin- 
der walls  in  a  gummy  deposit.  If  much  sulphur  is  in  the  fuel 
oil,  it  will  attack  the  cylinder  of  the  idle  engine. 

Another  installation  error  that  is  quite  prevalent  is  the  use  of  a 
water  drip  into  the  exhaust  line.  The  water  is  used  to  cool  the 
gases,  thereby  both  deadening  the  noise  of  exhaust  and  lowering 
the  back  pressure.  The  water  does  perform  its  mission  but  has 
the  objection  of  causing  the  exhaust  to  be  wet.  Because  of 
this  moisture  a  black,  tarry  deposit  will  settle  over  the  entire 
surroundings.  Increased  pipe  size  and  the  use  of  a  suitable  pit 
will  serve  just  as  well  without  this  objectionable  feature. 

Exhaust  Pits. — Every  low-compression  oil  engine,  no  matter 
where  installed,  should  be  provided  with  an  exhaust  pit.  It  is 
the  practice  of  some  manufacturers  to  furnish  a  cast-iron  exhaust 
pot,  which  is  located  close  to  the  engine.  While  this  assists  in 
dampening  the  noise  of  the  exhaust,  it  does  not,  by  any  means, 
take  the  place  of  a  pit. 

Low-compression  engines,  regardless  of  make,  when  the  in- 
jection apparatus  is  not  in  the  best  of  shape,  display  a  tendency 
to  allow  part  of  the  fuel  charge  to  blow  out  through  the  exhaust 
ports  while  it  is  in  a  liquid  condition.  This  is  especially  notice- 
able when  an  oil  having  a  heavy  asphaltum  base  is  used,  because 
the  cylinder  temperature  is  not  high  enough  to  vaporize  the  heav- 
ier portion  of  the  oil.  The  same  objection  frequently  is  raised 
against  heavy  fuel  oil  when  the  engine  is  operating  on  low  loads. 
On  low  loads  the  temperature  of  the  bulb,  or  other  hot  ignition 
device,  falls  so  low  that  it  is  unable  to  completely  vaporize  any 
of  the  fuel  oils  ordinarily  used.  As  a  consequence  some  of  the  oil, 
still  un vaporized,  passes  out  through  the  exhaust  ports  and  enters 
the  exhaust  pipe.  The  same  condition  of  unconsumed  fuel  en- 
tering the  exhaust  pipe  is  often  encountered  when  the  governor 
or  the  injection  nozzle  fails  to  cut  off  the  oil  supply  at  the  proper 
point. 

If  the  discharge  oil  is  trapped  in  the  pipe  or  in  an  exhaust  pot 
located  close  to  the  engine,  it  will  accumulate  until  it  is  set  afire. 


EXHAUST  PIPE  AND  PIT 


423 


The  exhaust  is  always  at  a  high  temperature,  around  800°  Fahren- 
heit, and  frequently  a  flame  blows  through  the  exhaust  ports  and 
ignites  this  residue.  Many  fires,  some  of  them  serious,  have 
resulted  from  the  use  of  an  exhaust  pot  or  muffler.  If  the 
employment  of  a  pot  is  decided  upon,  then  a  thimble  should  by 
all  means  be  placed  around  the  pipe  where  it  passes  through  the 
roof. 


l'Bo/1-s  Id'Long 


/2'5tack20'High 


•MSe  »«**• 


FIG.  333. — Modern  design  of  exhaust  pit. 

In  preference  to  the  pot,  a  concrete  exhaust  pit  should  be  con- 
structed outside  the  building.  It  is  a  good  plan  to  place  the  pit 
at  least  3  feet  from  the  building  wall,  although  5  feet  is  better. 
Means  must  be  provided  for  draining  away  the  residue  that 
accumulates  in  the  pit.  If  the  contour  of  the  land  permits, 
the  drain  should  have  an  open  end.  If  not,  it  can  be  run  to  a 
smaller  pit  and  a  bucket  placed  in  this  pit  below  the  drain.  In 
this'way  the  residue  will  collect  in  the  bucket  and  can  be  removed. 

Figure  333  shows  a  form  of  exhaust  pit  very  generally  adopted. 
It  is  provided  with  an  extra  exhaust-stack  pit  leading  from  the 
pit  proper.  While  this  is  of  assistance  in  deadening  the  noise, 
it  is  a  refinement  not  actually  required.  The  concrete  walls  should 
be  9  inches  thick  as  a  minimum,  and  reinforcing  rods  should 


424 


OIL  ENGINES 


be  used.  These  rods  will  resist  the  ordinary  strains  to  which  the 
walls  are  subjected.  The  top  can  be  made  either  of  a  boiler 
plate  covered  with  earth,  or  of  old  iron  rails  with  a  concrete  slab 
as  a  cover.  A  manhole  should  be  constructed  in  the  top,  both 
for  access  to  the  pit  and  for  safety  in  case  a -violent  explosion 
occurs. 

Another  good  form  of  pit  is  shown  in  Fig.  334.  Here  the  ex- 
haust pipe  A  enters  below  the  layer  of  rock  B  which  is  supported 
by  old  rails  or  iron  bars  and  serves  to  deaden  the  sound  of  the  ex- 


b= 

- 

r   O'    ,•  & 

.  B 
iii>^K*>sS»aPt^ 

if 

Drain  Pipe^ 

FIG.  334.  FIG.  335. 

Exhaust  pits. 

plosion.  Such  a  pit  is  well-nigh  noiseless  and  is  as  cheap  to  build 
as  a  less  efficient  one.  It  should  be  provided  with  a  manhole 
in  the  side,  below  the  layer  of  rock.  This  manhole  should  be 
fitted  with  a  thin  cover  held  in  place  by  two  small  studs  so  that, 
if  a  heavy  explosion  does  occur,  the  cover  will  blow  off  and  pre- 
vent damage  to  the  pit. 

Frequently  a  cylindrical  exhaust  pit  like  that  shown  in  Fig. 
335  is  used.  This,  however,  is  not  as  good  a  design  as  Figs.  333 
and  334  since  it  does  not  even  deaden  the  noise  of  the  exhaust. 
Furthermore,  as  it  has  no  drain,  the  residue  cannot  be  removed 
readily.  Figure  332,  showing  pipe  conduit,  also  outlines  a  type  of 
exhaust  pit,  or  pot,  that  is  used  in  some  installations.  It  is 
essentially  a  boiler  plate  tank  with  inlet  and  discharge  openings. 


EXHAUST  PIPE  AND  PIT  425 

It  has  the  disadvantage  of  high  initial  cost  and  no  advantage 
other  than  that  it  can  be  moved  in  case  the  power  plant  is  ever 
transferred  to  another  location. 

In  a  two-engine  installation  the  two  engine  exhausts  can  be  run 
into  one  exhaust  pit  that  is  partitioned  into  two  parts,  each  of 
which  has  a  manhole  and  a  stack.  This  reduces  the  cost  of  ex- 
cavation. 

There  is  a  large  variation  in  the  plans  of  different  engine  build- 
ers as  to  the  necessary  exhaust  pit  volume.  Some  call  for  entirely 
too  great  an  outlay  of  concrete  while  others  are  equally  as  thrifty 
in  the  dimensions  given.  If  the  pit  is  designed  on  the  basis  of 
1  cubic  foot  of  volume  for  each  horsepower  of  the  engine  rating, 
the  pit  will  be  ample  in  size  and  the  cost  reasonable. 

The  pit  should  be  so  located  that  its  top  will  be  a  few  inches 
below  the  ground  level.  The  exhaust  stack  is  best  held  to  the 
pit  by  means  of  a  cast-iron  flange.  If  a  flange  cannot  be  procured, 
four  lugs  riveted  on  the  stack  will  serve.  The  stack  should  have 
a  reinforcing  ring  both  at  the  top  and  bottom.  It  is  advisable 
to  have  the  stack  considerably  larger  than  the  exhaust  piping;  for 
instance,  if  an  exhaust  pipe  8  inches  in  diameter  is  used,  the  stack 
should  be  at  least  12  inches  in  diameter.  Owing  to  initial  cost 
it  is  customary  to  use  a  sheet-steel  stack  of  from  No.  8  to  No.  16 
gage.  Corrosion  in  the  stack  is  generally  severe,  and  a  light  gage 
steel  will  not  last  long.  The  stack  ought  never  be  made  of  less 
than  No.  10,  and  J^-inch  plate  will  prove  the  cheapest  in  the  end. 
It  is  good  practice  to  paint  the  stack  each  year  with  an  asphaltum 
stack  paint.  This  will  keep  down  the  corrosion  and  increase  the 
good  appearance  of  the  plant.  The  question  as  to  the  length  of 
stack  is  one  that  is  governed  by  the  location  of  the  plant.  A  good 
rule  is  to  always  have  its  top  at  least  10  feet  above  any  building 
close  by.  This  serves  to  carry  away  all  fumes  and  eliminates  the 
effect  of  the  air  waves  that  so  often  cause  windows,  for  blocks 
around,  to  rattle. 

Water  Circulating  Systems. — Every  oil  engine  demands  some 
form  of  water  circulating  system.  The  particular  system  most 
applicable  to  any  plant  depends  upon  many  factors.  The 
systems  most  used  may  be  classified  as:  Thermo-syphon,  Fresh 
Water,  Closed  Cooling  Tower,  and  Tank  and  Tower  Systems. 

Thermo-syphon  System. — The  thermo-syphon  principle  of 
circulating  water  is  generally  adopted  on  small  oil  engines  of 
25  h.p.  or  less.  It  consists  of  one  or  more  galvanized  steel 


426 


OIL  ENGINES 


tanks  that  are  connected  to  the  engine  water  jacket  by  an 
inlet  and  discharge  pipe.  The  water  in  the  cylinder  jacket  be- 
comes warm,  and  the  weight  of  the  heavier  cold  water  causes  it 
to  raise  up  the  pipe  A  and  to  flow  into  the  cooling  tank  where  its 
temperature  is  lowered  by  radiation  and  convection;  see  Fig. 
336.  The  cold  water  in  the  bottom  of  the  cooling  tank  flows 
through  the  inlet  pipe  B  to  displace  the  warm  water.  The  dis- 
charge pipe  A  must  be  provided  with  a  riser,  as  shown,  in  order 


FIG.  336. — Thermosyphon  cooling  system. 

to  prevent  any  air  pockets  and  to  allow  all  accumulations  of 
steam  or  water  vapor  to  escape.  The  advantage  of  this  system 
lies  in  its  simplicity  and  freedom  from  trouble.  Two  precautions 
must  be  observed.  First,  the  water  level  in  the  cooling  tanks 
should  be  maintained  at  least  4  inches  above  the  outlet  of  the 
discharge  or  hot-water  pipe.  If  it  falls  below  this  outlet,  the 
circulation  will  cease.  Second,  if  the  locality  is  subject  to  cold 
weather,  the  jacket  should  be  drained.  This  calls  for  a  three-way 
cock  in  the  cold-water  connection. 


EXHAUST  PIPE  AND  PIT 


427 


The  average  purchaser,  since  he  has  paid  so  much  for  his  oil 
engine,  is  usually  loathe  to  invest  any  great  amount  of  money  in 
his  steel  cooling  tanks.  The  result  is  a  cooling  system  much  too 
small  for  the  engine's  requirements.  It  is  customary  to  find 
tanks  with  a  total  capacity  of  around  20  gallons  of  water  per 
engine  horsepower,  while  the  smallest  value  that  should  be  con- 
sidered is  50  gallons  per  engine  horse-power.  The  warm  water 
loses  its  heat  by  surface  radiation  and  evaporation;  little  heat  is 
lost  through  the  tank  walls.  It  then  follows  that  the  larger  the 
diameter  of  the  cooling  tank  the  smaller  need  be  the  volume  of 
water.  This  factor  often  dictates  the  use  of  a  cypress  tank  with 
a  3-foot  stave.  A  tank  of  this  kind  costs  less  than  the  steel 
tanks  of  equal  cooling  capacity  and  will  last  much  longer.  The 
cypress  tank  can  be  mounted  on  a  platform  to  bring  its  top  above 
the  engine's  water  discharge  pipe.  It  can  safely  be  from  5  to 
10  feet  above  the  ground  level. 

Power  Head  Pump 
I  PuIkyWheel 
\  Belted  from 
\Engine  50Rpm. 


=  --— ^--n^yro-^v//////// 

Check  Valve     if""  Plunger  Rod 

,,  x   ''Cylinder 

f  ..-Discharge I" 


Well 


FIG.  337. — Fresh  water  system. 

Fresh-water  System. — When  water  can  be  secured  within 
30  or  40  feet  of  the  ground  surface,  the  most  economical  way  to 
cool  the  engine  is  by  the  fresh-water  system.  A  two-stroke- 
cycle  low-pressure  engine  loses  more  heat  to  the  jacket  than  does 
the  Diesel,  and  so  a  greater  amount  of  water  must  be  used.  A 
fair  value  upon  which  to  estimate  the  water  requirements  is 
70  Ibs.  of  water  per  b.h.p.  per  hour  or  1  Ib.  per  b.h.p.  per  minute. 
The  power  required  to  handle  this  water  from  a  depth  of  30  feet 


428  OIL  ENGINES 

and  through  the  jacket  will  not  exceed  one-half  of  1  per  cent,  of 
the  engine's  rating. 

If  the  water  is  over  16  feet  from  the  surface,  some  form  of  power 
pumping  head  with  an  extended  pump  cylinder  should  be  installed. 
The  pump  cylinder  is  best  placed  below  the  surface  of  the  water. 
This  arrangement  keeps  the  pump  primed  at  all  times  and  also 
prevents  the  plunger  rings  from  drying  out  when  the  engine  is 
idle.  The  best  cylinder  is  one  fitted  with  brass  poppet  valves 
and  with  the  pump  plunger  of  brass  with  at  least  four  leather 
rings,  while  the  cylinder  itself  should  be  brass,  or  brass-lined. 
The  working  head  can  be  belted  and  of  almost  any  design.  The 
well  is  best  placed  close  to  the  engine  in  order  to  allow  the  pump 
to  be  belted  direct  from  the  engine  shaft.  The  head  need  have 
no  idle  pulley,  for  frequently  the  belt  will  run  on  to  this  pulley 
and  the  pump  will  stop,  Fig.  337. 

If  the  water  is  within  16  feet,  a  belted  horizontal  force  pump 
is  by  far  the  best  that  can  be  used.  A  centrifugal  pump  for 
this  work  is  liable  to  lose  its  suction  and,  when  starting,  fre- 
quently must  be  primed  due  to  a  leaky  valve.  The  centrifugal 
pump  for  plants  using  low-pressure  engines  has  no  attraction 
other  than  its  low  price.  No  matter  what  pump  is  used  a  foot 
valve  should  be  included. 

With  this  fresh-water  system  it  is  essential  that  a  riser  pipe 
be  installed  with  a  small  tank  or  barrel  at  its  top  and  with  a  check 
valve  between  the  barrel  and  the  pump,  as  well  as  a  cock  in  the 
engine  line.  The  barrel  must  be  placed  at  a  height  sufficient  to 
prevent  it  from  overflowing.  This  storage  will  provide  water 
for  running  the  engine  until  the  pump  begins  to  pick  up  its  suc- 
tion when  started  up  at  the  commencement  of  the  day's  run. 
In  a  pumping  plant,  the  engine  jacket  can  be  connected  to 
the  pump  discharge  by  a  by-pass  line.  By  placing  a  gate  valve 
in  the  main  pump  discharge,  between  the  engine  jacket  connec- 
tions, the  flow  of  water  through  the  engine  can  be  adjusted  to 
suit  conditions.  The  amount  of  water  that  flows  through  the 
jacket  is  a  small  percentage  of  the  pump's  capacity;  consequently 
the  rise  in  temperature  of  the  water  discharge  is  not  noticeable 
and  forms  no  objection  to  the  use  of  the  water  for  drinking  or 
general  waterworks  purposes.  If  the  discharge  head  on  the  pump 
exceeds  75  feet,  this  method  of  handling  the  cooling  water  is  open 
to  objection  since  too  great  a  pressure  is  placed  on  the  thin 
jacket  walls  with  a  likelihood  of  fracturing  the  jacket.  In  in- 


EXHAUST  PIPE  AND  PIT  429 

stallations  where  the  pumping  head  is  great,  the  proper  method  is 
to  tap  the  engine  line  off  the  pump  discharge  with  a  regulating 
valve  in  this  line  and  to  allow  the  water  flowing  through  the 
jacket  to  run  into  the  sewer  or  drainage  ditch,  or  back  into  the 
well  if  water  be  scarce. 

Tank  and  Tower  System. — The  ideal  method  of  coping  with 
the  circulating  water  problem,  where  the  water  is  not  heavy  with 
mineral,  is  by  means  of  the  tank  and  tower  plan.  In  low-pressure 
engines,  since  they  are  usually  but  moderate  in  size,  the  storage 
tank  need  not  be  as  large  as  with  a  Diesel  engine.  A  tank  6  feet 
in  diameter  with  a  5  foot  stave  is  ample  for  a  50  h.p.  engine 
while  a  100  h.p.  engine  should  be  supplied  with  an  8X8  ft. 
tank.  The  tank  should  be  mounted  on  a  wooden  tower  at 
least  20  feet  high;  the  height  depends  on  the  surrounding 
buildings.  On  top  of  the  tank  are  placed  the  cooling  screens. 
The  cooling  apparatus  may  be  made  of  wooden  slats  in  the  form 
of  a  pyramid.  Any  ordinary  mechanic  can  build  this,  and  it  is 
as  efficient  as  the  more  expensive  designs.  Conical  sheet  pans 
superimposed  on  each  other,  quite  like  in  steam  condenser  prac- 
tice, are  used  in  many  plants.  The  objection  to  this  cooling 
tower  is  the  rapid  corrosion  of  the  galvanized  sheet-steel  pans. 

The  tank  and  tower  system  includes  a  sump  to  which  the 
engine  discharge  water  flows.  Since  a  positive  supply  of  water  is 
obtained  by  the  overhead  storage,  the  use  of  a  centrifugal  pump 
to  lift  the  water  from  the  sump  to  the  tower  is  permissible.  This 
pump  can  be  placed  close  to  the  engine  and  belted  direct  from 
the  shaft.  If  the  sump  can  be  located  so  that  the  water  level  is 
within  2  feet  of  the  engine  room  floor,  the  pump  can  be  placed  in 
a  small  pit  by  the  engine  and  the  intake  line  will  then  be  under 
a  slight  head  at  all  times.  This  eliminates  the  trouble  of  losing 
the  pump  suction.  The  pressure  line  from  the  tower  to  the  en- 
gine should  be  equipped  with  a  regulating  cock,  while  the  tank 
should  have  a  float  with  a  bell-ringing  attachment  to  guard 
against  the  danger  of  the  supply  giving  out  without  warning  to 
the  operator.  In  this  system  the  discharge  line  from  the  cylinder 
jacket  is  usually  provided  with  a  funnel  so  that  the  flow  of  water 
can  be  in  plain  view  at  all  times. 

The  Closed  Circulating  System. — In  this  design  the  water  is 
forced,  by  a  pump,  through  the  engine  jacket  and  out  over  a 
cooling  tower.  From  the  cooling  tower  it  drops  into  a  sump 
underneath,  from  which  the  pump  draws  it  again.  When  the 


430 


OIL  ENGINES 


engine  is  50  h. p.  or  less,  a  tower  such  as  that  outlined  in  Fig. 
338  is  cheap  to  build,  satisfactory  in  operation  and  has  a  fair 
life.  The  cooling  water  is  brought  from  the  engine  and  dis- 
charged at  a  height  sufficient  to  allow  it  to  flow  over  the  top  of 
the  tower.  The  tower  supports  a  number  of  IJ^-inch  pipes  branch- 
ing from  the  main  3-inch  discharge  header,  and  each  branch  has  a 
series  of  J^-inch  holes  drilled  along  its  top  surface.  A  rectangular 


FIG.  338. — Cooling  tower  for  engines  under  50  H. P. 

sheet  of  5-mesh  wire  netting  is  suspended  from  each  pipe.  The 
water  issues  from  the  holes  in  the  pipes  and  runs  down  the  vertical 
netting,  being  cooled  to  the  temperature  of  the  surrounding  air 
before  it  strikes  the  sump.  This  sump,  or  storage  tank,  may  be 
either  a  concrete  pit  or  a  cypress  tank  above  ground.  The  use 
of  a  pit  allows  the  tower  to  be  lower  and  the  engine  jacket  pres- 
sure head  less. 

Figure  332  outlines  a  very  excellent  cooling  system.  In  this 
design  the  circulating  water  pump  is  of  the  plunger  type  and  is 
an  integral  part  of  the  engine.  One  very  important  detail  is 
included — a  drain  valve  on  the  suction  line.  In  localities  where 


EXHAUST  PIPE  AND  PIT  431 

there  is  danger  of  frost,  the  lines  should  be  drained  every  cold 
night.  One  of  the  greatest  items  of  expense  in  engine  operation 
in  the  Northern-  climates  is  the  replacement  of  fractured  parts 
due  to  freezing.  This  type  of  tower  is  quite  suitable  for  instal- 
lations of  150  h.p.  or  less.  In  the  event  a  plant  possesses  more 
than  this  capacity,  the  cooling  systems  discussed  in  Chapter  XIII 
will  be  found  adaptable  for  low-pressure  engines  as  well. 

Because  of  the  danger  resulting  from  pump  failure  the  over- 
head tank  system  is  by  far  the  best.  In  case  the  first  cost  is 
considered  too  high  to  permit  of  its  use,  and  the  closed  system  is 
adopted,  the  circulating  pump  should  be  driven  direct  from  the 
engine  either  by  a  silent  chain  or  a  linkage.  In  no  case  is  a 
belted  pump  good  practice  where  the  closed  system  is  used.  The 
plunger  type  pump  is  more  suitable  for  a  circulating  system  than 
is  a  centrifugal  pump  even  though  hundreds  of  the  latter  are  in 
such  service.  The  centrifugal  pump  must  be  primed  on  starting. 
Frequently  the  suction  is  temporarily  stopped  by  leaves  or  the 
like.  If  extra  care  is  not  exercised,  the  pump  may  lose  its  suc- 
tion and  fail  to  maintain  the  flow  of  cooling  water. 

In  operation  it  is  quite  often  a  question  as  to  the  temperature 
the  discharge  water  should  have.  It  is  self-evident  that  the 
engine's  efficiency  will  improve  with  an  increase  in  cooling  water 
temperature.  With  heavy  oils  160°  Fahrenheit  is  not  too  hot, 
while  with  high-gravity  distillate  or  kerosene  125°  is  as  high  as 
can  be  used  successfully. 


CHAPTER  XXV 
AIR  STARTING  SYSTEMS.     OPERATING  TROUBLES 

Air  Starting  Systems. — In  engines  up  to  30  h.p.  an  air  starter 
is  not  required.  It  is  not  difficult  to  turn  these  small  engines 
back  against  the  compression  in  order  to  start.  In  the  larger 
engines  some  form  of  starter  is  imperative. 

An  air  starting  system  consists  of  an  air  storage  tank,  small  air 
compressor,  piping  and  the  engine  starter-valve  mechanism. 
The  capacity  of  the  tank  depends  on  the  engine  size:  a 
24X72  in.  tank  is  ample  for  engines  of  60  h.p.  or  less.  For 


FIG.  339. — Air  piping  arrangement. 

engines  from  60  h.p.  to  150  h.p.  two  tanks  24X60  in.  should 
be  used.  These  tanks  should  be  built  for  200  pounds  working 
pressure,  and  the  seams  are  preferably  welded.  The  air  piping 
should  be  constructed  of  extra  heavy  pipe  and  malleable  fittings. 
The  pipe  lines  should  be  provided  with  a  drip  or  drips  at  the 
low  points,  while  the  tanks  should  have  drip  cocks  and  safety 
valves. 

The  types  of  air  compressors  used  are  quite  varied  as  to  size 
and  design.     Since  the  air  is  used  but  a  few  minutes  daily,  the 

432 


AIR  STARTING  SYSTEMS  433 


air  compressor  can  be  quite  small.  A  2X2J^  in.  compressor 
is  much  used  in  installations  below  100  h.p.  capacity.  For 
larger  installations  a  3X3  in.  or  3J^X3  in.  compressor  is  more 
suitable.  If  the  compressor  is  air-cooled,  the  plant  piping  is 
greatly  simplified,  and  the  compressor  operation  is  just  as  satis- 
factory. A  motor-driven  machine  is  very  attractive,  although 
in  the  small  plants,  as  a  matter  of  cost,  the  compressor  is  best 
belt-driven  from  the  engine  shaft.  Where  this  plan  is  adopted, 
a  small  gasolene  engine  should  be  installed  to  operate  the  com- 
pressor in  case  the  air  tanks  lose  their  charge,  similar  to  Fig.  339. 
In  all  installations  the  discharge  from  the  pump  should  enter  the 
top  of  the  air  tank,  as  should  also  the  line  to  the  engine  starting 
valve.  This  eliminates  the  danger  of  water  settling  or  condens- 
ing in  the  pipe  line. 

A  number  of  arrangements  for  starting  the  engine  are  em- 
ployed. The  majority  of  builders  furnish  some  form  of  quick- 
opening  valve.  This  valve  is  manipulated  by  the  operator.  The 
greatest  objection  to  the  hand-controlled  valve  is  the  difficulty 
of  opening  it  when  the  piston  is  in  the  proper  position.  Usually 
it  is  necessary  to  give  the  engine  several  air  charges  as  the  fuel 
charge  is  slow  in  igniting.  The  only  way  to  distinguish  the 
proper  point  for  starting  the  air  injection  is  by  means  of  a  mark 
on  the  wheel.  As  the  wheel 
turns  over,  it  is  no  easy  task 
to  jerk  open  the  valve  at  the 
precise  moment. 

Fairbanks-Morse  Air  Valve. 

-The  drift  of  present-day  air    '  .....   <&&M""  6oskef 

starting  design  is  to  provide 
some  form  of  mechanical- 
controlled  valve.  Figure  340 
is  the  starter  used  on  the 

.      ,  FIG.  340.—  Fairbanks-Morse  Co.  vertical 

Fairbanks-Morse  vertical  en-  air  starting  valve. 

gines.     When  the  engine  is  in 

operation,  a  globe  valve  in  the  air  line,  not  shown,  is  closed,  cutting 
off  the  air.  This  removal  of  air  pressure  from  the  starting  valve 
disk  allows  the  spring  to  move  the  valve  stem  A  from  engagement 
with  the  starting  cam  B.  In  starting  the  engine  the  flywheel  is 
barred  over  until  the  piston  is  about  4  inches  past  top  dead-center. 
The  globe  valve  is  opened  and  the  air,  blowing  past  the  starting 
valve  C,  enters  the  cylinder,  causing  the  piston  to  move.  The 


434  OIL  ENGINES 

air  pressure  on  the  valve  disk  C  holds  the  stem  A  in  contact  with 
the  cam  B,  and,  as  soon  as  the  cam  nose  is  passed,  the  air  pressure 
against  the  valve  disk  C  closes  the  starting  valve.  As  the  engine 
turns  over,  the  nose  again  opens  the  air  valve,  allowing  another 
charge  to  blow  into  the  cylinder.  This  action  is  repeated  until 
the  operator  closes  the  globe  valve.  Since  the  starting  arrange- 
ment is  connected  to  only  one  cylinder  in  the  multi-cylinder 
engines,  the  other  cylinder  can  begin  to  fire  while  the  starter  is 
still  in  operation.  In  the  single-cylinder  engines,  it  is  always  ad- 
visable to  give  the  engine  at  least  three  charges  of  air  before 
closing  the  globe  valve.  This  will  give  sufficient  impetus  to 
the  flywheel  to  enable  it  to  turn  over  in  case  the  first  fuel  charge 
fails  to  ignite.  To  prevent  the  products  of  combustion  from 
blowing  back  into  the  air  lines,  a  check  valve  is  mounted  on 
the  cylinder. 

Two  minor  precautions  should  be  observed.  The  check 
valve  seat  must  be  cleaned  and  ground  occasionally  to  eliminate 
all  danger  of  any  blowing  into  the  air  line.  The  air-starter 
spring  D  must  have  sufficient  tension  to  pull  the  stem  out  of 
contact  with  the  cam.  If  the  spring  breaks  or  if  the  stem 
becomes  dry  and  dirty,  the  end  of  the  stem  will  continue  to  touch 
the  cam  nose  while  the  engine  is  running.  This  will  speedily 
mushroom  the  ends  of  the  stem. 

Primm  Air  Starter. — The  Primm  engine  employs  a  very  simple 
mechanism.  This  consists  of  a  double-seated  valve  which  is 
actuated  by  a  push-rod.  This  push-rod  is  moved,  through  a  bell- 
crank  arrangement,  by  a  cam  mounted  on  the  flywheel  hub.  The 
operator  follows  practically  the  same  procedure  as  with  the  startej* 
already  discussed.  The  only  attention  demanded  is  the  grind- 
ing of  the  starter  valve. 

Mietz  and  Weiss  Air  Starter. — On  some  of  the  Mietz  and 
Weiss  vertical  engines  the  form  of  starter  shown  in  Fig.  341  is 
used.  The  rocking  or  corliss  type  of  starting  valve  A  is  actuated 
by  an  eccentric  on  the  engine  shaft.  As  indicated  in  the  draw- 
ing, it  is  equipped  with  a  check  valve  B,  as  well  as  a  disk  valve 
C,  immediately  at  the  cylinder  to  shut  off  the  air  after  the  engine 
is  in  operation.  In  starting  it  is  only  necessary  to  bar  the  engine 
a  few  degrees  past  upper  dead-center  and  open  the  hand-con- 
trolled valve.  The  starter  eccentric  will  then  open  and  close 
the  rocking  air  valve  at  the  proper  times  until  the  air  supply  is 
cut  off,  and  the  engine  begins  firing. 


AIR  STARTING  SYSTEMS 


435 


Starting  an  Engine. — All  engines  have  minor  differences  in  the 
method  of  starting.  The  following  is  the  procedure  that  applies 
to  practically  all  of  the  low-pressure  engines. 

The  engine  should  first  be  barred  over  to  its  starting  position. 
Usually  the  flywheel  carries  a  mark  to  indicate  when  this  position 
is  reached.  If  not,  the  engineer  can  locate  the  position  of  the 
crank  by  means  of  the  split  in  the  flywheel  hub,  if  it  be  of  this 
design.  After  Locating  the  crank  position,  the  wheel  should  be 
turned  until  the  crank  is  about  30  degrees  past  the  rear  dead-center. 


Air  Inlet 


FIG.  341. — Meitz  &v  Weiss  air  starter. 

The  indicator  or  test  cock  on  the  engine  should  be  opened. 
In  fact,  it  is  better  to  open  it  before  turning  the  engine  over  since 
it  will  relieve  the  compression.  The  starting  torch  is  next  ignited 
and  the  flame  directed  against  the  ignition  device,  whatever 
design  be  used — hot  ball,  hot  tube  or  hot  head.  While  the 
torch  is  heating  the  igniter,  the  operator  should  fill  up  the  oil 
and  grease  cups. 

The  fuel  should  next  be  admitted  into  the  pump.  After  the 
torch  has  been  burning  for  some  minutes,  the  fuel  pump  should 
be  operated  by  hand  until  the  plunger  works  hard.  This  shows 
that  the  discharge  oil  line  to  the  nozzle  is  filled.  The  pump 
handle  should  now  be  given  about  three  strokes,  injecting  some 
of  the  fuel  into  the  cylinder.  If  this  results  in  a  blue  vapor 
issuing  from  the  test  cock,  it  can  be  assumed  that  the  igniter  is 


436  OIL  ENGINES 

hot  enough.  The  test  cock  is  now  closed,  and  a  final  stroke  is 
given  to  the  pump. 

The  air-starter  mechanism  is  next  operated,  and  the  engine  is 
turned  over.  Ordinarily  the  engine  will  riot  explode  on  the  sec- 
ond revolution,  and  it  is  generally  advisable  to  allow  at  least  three 
air  charges  to  enter  the  cylinder.  The  engine  should  now  ignite 
the  fuel.  If  it  fails  to  do  so,  the  operator  should  discontinue  his 
efforts  to  start  the  engine  with  the  air  and  should  proceed  to  heat 
the  igniter  to  a  higher  temperature.  A  cold  igniter  is  almost  al- 
ways the  cause  of  a  starting  failure. 

When  the  engine  begins  to  fire  the  fuel,  in  most  cases,  there  is  a 
decided  pound  or  preignition.  The  operator  should  restrain  the 
motion  of  the  pump  plunger,  preventing  any  great  amount  of 
fuel  from  being  ignited.  Since  the  governor  is  in  its  lowest  posi- 
tion, the  fuel  charge  at  starting  is  heavier  than  when  fully  loaded. 
A  few  strokes  of  the  piston  will  allow  all  the  fuel  in  the  cylinder 
to  burn,  and  the  stroke  of  the  pump  can  be  lengthened  a  little. 
Until  the  engine  is  up  to  full  speed,  the  engineer  should  continue 
to  restrain  the  stroke  of  the  fuel  pump. 

The  cooling  water  should  now  be  turned  on;  it  is  best  to  open 
the  valve  slowly,  thus  allowing  the  cylinder  head  to  cool  off  grad- 
ually. •  If  the  opening  of  the  cooling-water  valve  is  neglected  until 
the  engine  becomes  thoroughly  hot,  a  fractured  head  will,  in 
most  cases,  occur  when  the  water  does  strike  it.  Frequently, 
when  starting,  the  connecting-rod  emits  a  snappy  or  whip-like 
sound,  while  the  piston  slams  if  worn  at  all.  This  merely  indi- 
cates that  the  engine  is  coming  up  to  speed  too  rapidly,  and  the 
operator  should  lessen  the  amount  of  fuel  injected  by  control  of 
the  pump  plunger  stroke. 

As  soon  as  the  engine  is  at  normal  speed  the  water  injection 
should  be  started,  provided  the  engine  is  of  a  design  using  water 
in  the  cylinder. 

If  the  engine  is  belted  to  its  load  through  a  friction  clutch  or 
clutch  pulley,  the  clutch  should  now  be  thrown  in.  If  the  engine 
is  belted  or  direct-connected  to  a  generator,  the  line  switch  should 
be  closed  and  the  voltage  on  the  machine  gradually  built  up. 
In  two-unit  plants,  where  the  generators  operate  in  parallel, 
special  care  should  be  exercised  in  order  that  the  two  gene- 
rator voltages  be  identical  before  they  are  thrown  together; 
this  applies  to  direct-current  machines.  If  the  machines  are 
alternating  current,  it  is  imperative  that  they  be  in  phase  before 


AIR  STARTING  SYSTEMS  437 

being  paralleled.  The  most  feasible  arrangement  whereby  the 
paralleling  can  be  easily  accomplished  is  the  use  of  a  synchron- 
oscope.  A  plant  with  a  total  capacity  of  50  kw.  should  be 
equipped  with  this  instrument.  In  the  small  plants,  or  in  larger 
ones  where  it  is  impossible  to  purchase  the  synchronoscope,  the 
pilot  lamp  device  should  be  used.  In  no  plant  should  an  engineer 
depend  on  chance  in  the  matter  of  paralleling  alternators. 

Temperature  of  Cooling  Water. — The  proper  temperature  of 
the  jacket-cooling  water  is  a  matter  that  must  be  determined  by 
experiment  on  the  particular  engine  used.  Engines,  even  of  the 
same  horsepower  and  same  manufacture,  show  a  decided  varia- 
tion in  the  water  temperature  most  favorable  for  efficient  opera- 
tion. The  characteristics  of  the  fuel  oil  used  have  considerable 
effect.  As  a  general  rule,  it  may  be  stated  that  with  oils  under 
32°  Baume  gravity  the  temperature  of  the  discharge  cooling 
water  should  be  maintained  around  150°  to  160°  Fahrenheit.  For 
lighter  oils,  such  as  distillates  up  to  42°  Baume*,  the  temperature 
should  not  exceed  140°  Fahrenheit,  and  usually  125°  Fahrenheit 
will  prove  satisfactory.  With  the  heavier  oils  it  is  necessary 
that  the  cylinder  and  head  be  kept  fairly  warm  in  order  to 
thoroughly  vaporize  the  fuel  charge. 

Lubrication. — As  with  the  cooling-water  temperature,  the 
amount  of  lubricating  oil  that  is  required  on  any  engine  cannot 
be  stated  with  any  degree  of  certainty.  Much  depends  on  the 
fuel  used,  the  condition  of  the  engine  and  the  particular  design 
of  the  unit.  Where  either  splash  lubrication  or  oil  cellars  are 
used  for  the  lubrication  of  the  bearings  and  crank  pin,  if  600 
h.p.-hr.  are  produced  per  gallon  of  lubricating  oil  the  oper- 
ator can  feel  that  he  is  securing  efficiency  in  his  oiling.  It 
should  be  understood  that  usually  an  engine  will  require  as 
much  lubrication  on  half  as  on  full  load.  Consequently,  if  the 
engine  be  at  half  load,  the  horsepower  per  gallon  of  lubricating 
oil  will  be  one-half  of  the  above.  If  kerosene  or  high-gravity  dis- 
tillate, usually  termed  "  stove  oil,"  be  used,  the  amount  of  lubri- 
cation required  for  the  cylinder  is  practically  doubled. 

The  following  table  represents  a  fair  average  for  an  engine  of 
above  40  h.p.  per  cylinder. 

Piston  pin 10  drops  per  min. 

Crank  pin 30  drops  per  min. 

Cylinder,  exhaust  side  40  drops  per  min. 

Cylinder,  air-port  side 50  drops  per  min, 


438  OIL  ENGINES 

In  engines  where  the  cylinder  is  oiled  at  three  points,  the  amount 
of  oil  for  the  three  should  approximate  the  total  for  the  two 
values  above.  If  the  piston  pin  is  lubricated  by  scooping  up 
oil  from  the  cylinder  walls,  of  course  the  oil  to  the  cylinder  must 
be  increased. 

Each  oil  company  has  a  particular  oil  that  usually  is  suitable 
for  low-pressure  engines.  It  is  hardly  profitable  for  an  engineer 
•to  experiment  with  the  various  oils  offered,  and  the  most  satis- 
factory oil  to  purchase  is  the  one  recommended  by  the  builder 
of  the  engine.  All  engine  builders  are  much  interested  in  the 
lubrication  problem  and  are  in  a  position  to  conduct  extensive 
tests  on  all  the  lubricants  on  the  market.  They  seldom  are 
prejudiced  in  this  matter,  and  their  recommendations  can  be 
followed  with  confidence. 

Operation  Troubles.  Engine  Smokes. — At  least  50  per  cent, 
of  the  engines  in  use  show  a  decided  inclination  toward  a  smoky 
exhaust.  Since  this  symptom  of  imperfect  operation  is  so  appar- 
ent, the  most  inexperienced  engineer  cannot  overlook  it.  Any 
one  of  a  number  of  misadjustments  may  be  the  cause  of  this 
dark-colored  exhaust. 

The  hot  bulb  or  other  ignition  device  may  be  too  cold,  thus 
failing  to  vaporize  all  the  oil,  which  then  exhausts  while  in  a 
liquid  or  at  least  a  saturated  condition.  The  cold  bulb  may  be 
due  to  two  causes — the  bulb  may  be  too  large,  thereby  exposing 
too  great  an  exterior  surface  to  the  cooling  action  of  the  air;  or 
carbon  deposits  may  cause  the  interior  to  be  closed,  shutting  off 
the  absorption  of  heat.  If  the  device  be  water-cooled,  the  jacket 
may  be  absorbing  too  much  of  the  heat  from  the  combustion 
chamber.  In  those  engines  using  a  hot  bolt,  the  bolt  may  be 
burned  or  oxidized  to  such  an  extent  that  there  is  only  a  small 
amount  of  metal  left  in  the  bolt  to  absorb  the  heat  of  .combus- 
tion. The  proper  adjustments  to  relieve  these  various  defects 
are  apparent. 

Frequently  an  over-abundant  supply  of  injection  water 
lowers  the  temperature  of  the  entire  cylinder  and  ignition  device, 
preventing  proper  vaporization.  The  heavier  oil  particles,  even 
though  partially  gasified,  will  then  blow  out,  giving  a  decidedly 
dark  hue  to  the  exhaust,  unless  an  unusually  good  exhaust  pit 
is  used  to  trap  the  free  oil  particles.  This  condition  is  always 
accompanied  by  the  loss  of  power  in  the  engine.  The  water 
should  always  be  reduced  in  quantity  until  the  engine  begins  to 


AIR  STARTING  SYSTEMS  439 

preignite;  the  water  supply  should  then  be  increased  a  slight 
amount — sufficient  to  destroy  the  preignition  sound. 

On  the  other  hand,  too  little  injection  water  may  produce  a 
smoky  exhaust.  This  applies  where  a  heavy  fuel  is  used.  The 
water  injected  in  the  cylinder  seems  to  assist  the  heavier  particles 
in  burning,  even  though  these  heavier  parts  do  not  vaporize. 
If  the  water  supply  is  insufficient,  these  heavier  particles  of  oil 
blow  out  in  a  liquid  state. 

If  a  dirty  fuel  oil  be  used,  the  injection  nozzle  check  valve  will 
probably  cut,  thereby  imperfectly  sealing  the  nozzle.  The  oil 
which  drips  into  the  cylinder  during  the  latter  part  of  the  power 
stroke  does  not  burn.  This,  of  course,  will  cause  a  dark  exhaust. 

Another  very  frequent  cause  of  a  smoky  exhaust  lies  in  the  use 
of  entirely  too  much  lubricating  oil  in  the  cylinder.  If  more  of 
this  oil  is  supplied  to  the  cylinder  walls  than  the  gas  flame  will 
completely  burn,  the  unburned  part  will  settle  in  the  exhaust 
ports  and  pipe.  The  exhaust  gases,  as  they  pass  through  the 
exhaust  line,  pick  up  this  oil  and  blow  it  out  the  discharge. 

Low-compression  pressure  is  largely  responsible  for  an  objec- 
tionable color  to  the  exhaust.  If  the  compression  leaks  past  the 
piston,  the  pressure  and  temperature  in  the  cylinder  and  bulb 
will  not  be  sufficient  to  vaporize  and  ignite  the  fuel.  It  follows 
that  at  least  the  heavier  fuel  particles  will  blow  out  the  exhaust 
in  an  unconsumed  state. 

Preignitions. — If  the  ignition  device  is  at  too  high  a  tempera- 
ture, the  vaporized  fuel  will  mix  with  the  air  charge  early  in  the 
compression  stroke.  The  natural  result  of  the  mixing,  already 
discussed  in  a  previous  chapter,  is  premature  combustion  before 
the  piston  reaches  dead-center.  Much  depends  on  the  character 
of  the  oil.  If  it  vaporizes  rapidly,  the  preignitions  will  continue. 
If  water  injection  is  not  used,  or  if  the  bulb  is  not  equipped  with 
some  form  of  a  cooling  jacket,  which  may  be  provided  with  a 
valve  to  control  the  bulb  temperature,  it  is  necessary  to  alter  the 
size  of  the  hot  ball.  If  the  bulb  be  made  larger,  it  will  radiate 
heat  faster,  thus  maintaining  itself  at  a  lower  temperature.  It  is 
a  wise  precaution  for  the  engineer  to  keep  two  or  three  bulbs  or 
tubes  of  different  sizes  on  hand  so  that  this  change  can  be  made 
without  any  delay.  Another  remedy  is  the  adjustment  of  the 
fuel  injection  timing,  making  it  occur  later  in  the  compression 
stroke. 

If  the  load  be  around  the  engine's  full  rating,  and  a  light  fuel 


440  OIL  ENGINES 

is 'used,  the  vaporized  charge  has  too  large  a  volume  to  be  con- 
tained in  the  combustion  chamber.  Expanding  into  the  cylinder 
proper,  it  mixes  with  the  air  and  ignites.  If  the  fuel  is  of  light 
gravity,  of  course  it  will  ignite  earlier  in  the  compression  stroke. 
This  tendency  to  preignite  at  full  load  is  more  evident  in  "dry" 
engines  than  in  those  making  use  of  water  injection. 

Where  the  injection  nozzle  leaks,  this  oil  drip,  which  does  not 
blow  out  the  exhaust,  is  trapped  in  the  cylinder.  Even  though 
the  cylinder  temperature  is  fairly  low,  the  interval  of  time,  during 
which  the  piston  is  compressing  the  air  charge,  is  ample  to  allow 
this  fuel  to  vaporize  and  ignite  very  early  in  the  stroke. 

If  the  fue.l  used  possesses  a  low  flash  point,  as  in  case  of  kero- 
sene, the  tendency  of  the  oil  to  ignite  prematurely  is  always 
present.  A  more  liberal  supply  of  injection  water  will  cool  the 
hot  device  and  cylinder,  thereby  reducing  the  preignition. 

Strange  as  it  may  seem,  a  cold  hot  bulb  or  other  ignition  device 
will  occasion  preignitions  as  will  also  a  bulb  when  too  hot.  If 
the  bulb  is  cold,  the  fuel  charge  will  not  burn  completely.  The 
unconsumed  portion  blows  out  the  exhaust.  Due  to  imperfect 
scavenging,  some  of  the  fuel  remains  in  the  cylinder  where  it 
gradually  vaporizes  and  ignites  on  the  succeeding  compression 
stroke.  This  oil  more  frequently  collects  in  the  exhaust  passages 
where  a  blast  of  hot  exhaust  gases  ignites  it,  producing  what  is 
mistakenly  termed  preignitions,  although  it  is  more  in  the  nature 
of  a  back-fire. 

Excessive  use  of  water  injection  cools  the  hot  device,  causing 
the  same  trouble  just  mentioned. 

An  incorrect  governor  adjustment  will  produce  preignitions  by 
injecting  too  great  an  amount  of  oil  or  by  allowing  the  normal 
injection  to  commence  too  early  in  the  compression  stroke.  This 
is  more  evident  when  using  light  fuels. 

The  major  part  of  the  troubles  discussed  are  of  interest  only  to 
the  operator.  The  plant  owner  does  not  display  a  great  amount 
of  concern  until  the  engine  begins  to  lose  power  and  the  factory 
machinery  lags  in  its  work.  To  satisfactorily  operate  the  power 
plant  the  engineer  must  understand  those  things  which  cause 
the  engine  to  lose  its  power  capacity.  The  causes  can  be  listed 
briefly  as  loss  of  compression;  cold  hot  bulb;  too  heavy  fuel 
oil;  water  in  the  fuel  oil;  governor  or  pump  out  of  adjustment; 
leaky  injection  nozzle;  too  much  water  injection;  preignitions; 
leaking  air  compressor,  whether  it  be  crankcase  or  rear  of  cylinder 


AIR  STARTING  SYSTEMS  441 

compression;  clogged  oil  line;  and  in  a  four-stroke-cycle  engine 
leaky  valves  or  incorrect  valve  timing.  The  engineer  can  easily 
understand  the  particular  adjustment  necessary  in  each  event. 
The  items  that  cause  the  most  trouble  are  loss  of  compression, 
water  in  the  oil,  leaky  injection  nozzle  and  defective  pump  valves. 

Engine  Pounds. — To  the  inexperienced  engineer  a  pound  in 
the  engine  is  a  source  of  worry  and  bewilderment.  Most  of  the 
pounding  can  be  attributed  to  four  things — loose  crank-pin  or 
piston-pin  brasses;  worn  main  bearings;  worn  pistons;  and  pre- 
ignitions. 

A  worn  piston  pin  or  crank  pin  gives  out  a  dull  pound  as 
the  piston  starts  back  on  the , compression  stroke,  although  fre- 
quently it  shows  up  as  the  piston  passes  the  rear  dead-center. 
This  sound  is  different  from  a  preignition  and  is  seldom  found  on 
a  new  engine.  The  proper  remedy  is  the  adjusting  of  the  partic- 
ular brass  that  is  worn.  "  Jumping"  the  piston  and  connecting- 
rod  will  reveal  which  bearing  is  at  fault. 

The  wear  in  the  main  bearings  will  sometimes  cause  a  pound  as 
the  piston  passes  dead-center.  The  shaft  always  " jumps," 
and  the  engineer  can  readily  detect  the  bearing  that  is  worn. 

If  the  piston  is  badly  worn,  it  will  emit  a  slapping  sound  that 
is  quite  different  from  the  bearing  pounds.  As  discussed  in  the 
chapter  on  pistons,  a  new  piston,  or  in  all  events  replacement  of 
the  worn  rings,  is  the  remedy  for  this  slapping. 

The  sound  of  preignitions  in  the  cylinder  can  hardly  be  mis- 
taken for  anything  else.  It  is  usually  sharp  and  clearly  defined. 
Any  of  a  variety  of  misadjustments  will  cause  preignitions,  as 
already  discussed. 

The  elimination  of  any  of  the  troubles  enumerated,  which 
might  be  present,  along  with  liberal  lubrication  of  all  the  engine 
parts,  will  result  in  a  smooth-running  machine. 

Stopping  the  Engine. — If  the  engine  is  a  single-cylinder  unit, 
the  stroke  of  the  fuel  pump  should  be  gradually  reduced  by 
means  of  the  handle.  If  the  pump  is  stopped  immediately 
without  this  preliminary  restraint,  the  engine  will  pound  badly. 
If  the  unit  be  a  multi-cylinder  engine,  the  fuel  to  all  but  the 
starting  cylinder  should  be  cut  off  and  the  starting  engine  used 
to  gradually  bring  the  engine  to  a  state  of  rest. 

When  the  engine  has  almost  come  to  a  standstill,  the  lubricat- 
ing oil  pump  should  be  given  several  strokes  by  hand  in  order 
to  supply  a  liberal  amount  of  oil  to  all  the  parts.  The  fuel  line 


442  OIL  ENGINES 

to  the  pump  should  be  drained,  and  the  engine  indicator  or  test 
cock  opened.  If  the  engine  is  to  be  idle  for  more  than  a  day  or 
two,  the  oil  from  the  crankcase  and  main-bearing  cellars  should 
be  drawn  off.  The  crankcase  cover  should  be  opened  to  allow  the 
engine  to  cool  unless  the  unit  be  in  a  dusty  location.  The  cooling 
water  should  be  allowed  to  circulate  for  at  least  thirty  minutes 
after  the  engine  is  stopped.  If  there  is  any  danger  of  frost,  the 
cylinder  jacket  and  water  line  should  be  drained. 

The  operator  should  carefully  examine  all  the  engine  bearings, 
paying  particular  attention  to  the  crank-pin  brasses.  Using 
a  small  pinch  bar,  this  brass  should  be  tested  for  clearance  as 
well  as  side  play.  If  the  brass  seem$  unusually  warm,  it  should 
be  disassembled  and  the  oil  grooves  cleaned  out.  Any  rough 
spots  in  the  babbitt  should  be  scraped  smooth.  If  the  crank- 
case  is  enclosed,  it  should  be  drained  and  the  slimy  deposit  at 
the  bottom  mopped  out  with  a  handful  of  waste. 

These  are  the  points  that  should  be  observed  each  time  the 
engine  is  stopped  for  inspection  or  for  a  shut-down.  If  the  shut- 
down is  only  for  a  few  hours  and  is  a  matter  of  frequent  occur- 
rence, this  inspection  of  the  bearings  is  not  necessary.  No  matter 
how  short  is  the  period  of  shut-down,  the  engine  should  be  thor- 
oughly wiped  with  waste  or  rags.  Nothing  is  so  conducive  to  a 
long-lived  engine  as  thorough  cleanliness.  All  the  small  moving 
parts,  such  as  make  up  the  fuel  pump  and  governor  assembly, 
must  be  kept  clean. 


Spring  Scale  200  Ibs. 


Scale  200  Ibs. 


FIG.  342.— De  Lavergne  type  DH  24°      FIG.  343.— De  Lavergne  type  DH  32° 
crude  oil.  Be  fuel  oil. 

Low-pressure  Indicator  Cards. — The  use  of  the  indicator  is 
not  general,  even  where  the  units  are  Diesels.  The  operator  of 
small  low-pressure  engines  usually  does  not  feel  justified  in 
investing  in  an  indicator;  where  the  engine  is  above  50  h  p.,  this 
accessory  is  almost  indispensable  if  economy  in  operation  is  to  be 
achieved.  By  the  intelligent  use  of  the  indicator  an  engineer  is 
in  the  position  to  know  when  his  engine  is  not  working  efficiently. 


AIR  STARTING  SYSTEMS  443 

Frequently,  a  preignition  sound  is  mistaken  for  a  pound  pro- 
duced by  a  worn  bearing.  An  indicator  card  would  reveal  at  once 
if  the  fuel  was  exploding  prematurely.  Again,  the  engine  may 
labor  and  the  engineer  think  the  load  is  excessive,  whereas  the 
trouble  may  be  due  to  late  injection  or  delayed  combustion. 

The  different  fuels  have  marked  differences  in  behavior,  as 
revealed  on  the  card.  Figure  342  is  a  card  from  a  De  La  Vergne 
Type  D.H.  engine  using  24°  Baume  crude  oil.  The  ignition 
is  a  trifle  late  since  the  vertical  line  slopes  to  the  right,  showing 
that  the  piston  had  passed  dead-center  before  the  fuel  ignited. 
The  horizontal  hook  "a"  indicates  that,  after  most  of  the  fuel 
exploded,  there  was  a  percentage  of  heavier  particles  that  con- 
tinued the  combustion.  The  compression  pressure  at  the  point 
"  1 "  reached  200  Ibs.  per  sq.  inch  while  the  maximum  explosive 
pressure  ran  above  360  pounds.  The  fact  that  the  fuel  did  not 
ignite  just  before  dead-center  can  probably  be  attributed  to  a 
cold  combustion  chamber.  With  this  engine  the  fuel  injection 
occurs  considerably  ahead  of  dead-center,  and  evidently  then  the 
trouble  was  not  delayed  injection. 

Figure  343  is  a  card  from  the  same  engine  while  using  32° 
Baume  fuel  oil.  The  charge  exploded  about  6  degrees  ahead 
of  dead-center,  where  the  compression  was  around  175  Ibs.  per  sq. 
inch .  The  maximum  explosive  pressure  reached  380  pounds .  This 
card  is  well-nigh  ideal  for  a  low-pressure  engine.  The  explosion 
had  better  occur  a  trifle  before  dead-center  than  after  the  piston 
commences  its  return  stroke. 


FIG.    344. — Fairbanks- Morse   type   Y      FIG.  345. — Fairbanks- Morse  oil  engine 
indicator  card.  kerosene  fuel. 

Figure  344  is  a  card  from  a  50  h.p.  Fairbanks-Morse  Type  Y 
engine  running  at  257  r.p.m.  The  compression  at  "a"  reaches  160 
pounds  while  the  maximum  cylinder  pressure  exceeds  375  pounds. 
The  fuel  used  was  27°  fuel  oil,  which  resulted  in  a  flattening  of 
the  explosion  peak.  The  waves  in  the  expansion  line  are  not  due 
to  delayed  explosion  but  are  caused  by  the  inertia  of  the  indicator 


444  OIL  ENGINES 

piston  and  other  parts.  The  combustion  was  a  trifle  late,  which 
produced  a  slight  pound  in  the  piston-pin  bearing.  On  investiga- 
tion the  piston-pin  bearing  was  found  to  be  somewhat  worn.  For 
an  engine  operating  at  a  speed  of  257  r.p.m.  the  card  is  exceed- 
ingly satisfactory. 

Figure  345  is  an  example  of  the  freak  cards  occasionally  taken 
with  the  indicator.  The  engine  was  the  same  from  which  Fig. 
344  was  secured  but  at  a  later  date.  The  fuel  used  was  kerosene. 
The  compression  reached  approximately  100  pounds  when  the  kero- 
sene charge  in  the  combustion  chamber  fired.  Due  to  the  inertia 
of  the  indicator  piston  and  levers  the  pencil  point  jumped  to 
'"6,"  far  beyond  the  actual  cylinder  pressure  at  this  position  of 
the  piston.  The  pencil  then  moved  downward  toward  its  true 
position,  but  the  inertia  of  the  spring  forced  the  pencil  to  "d," 
whereupon,  being  stable  now,  the  point  moved  up  approximately 
along  its  true  course  to  the  maximum  point  "c."-  This  erratic 
behavior  of  the  indicator  mechanism  completely  distorted  the 
card,  and  the  events  as  outlined  on  this  card  are  by  no  means  rep- 
resentative of  the  actual  occurrences  in  the  cylinder.  The  dotted 
line  from  "a"  to  "c"  probably  is  the  path  the  pencil  should  have 
taken.  Regardless  of  the  action  of  the  indicator,  this  card  shows 
that  if  kerosene  is  to  be  used  in  an  engine  without  water  injec- 
tion, either  the  fuel  must  be  injected  practically  at  dead-center 
or  the  compression  must  be  reduced.  Due  to  the  design  of 
connecting-rod  on  this  engine,  no  great  alteration  in  the  compres- 
sion is  possible,  making  it  necessary  to  delay  the  injection  pump 
action. 

Figure  346  is  a  card  from  a  Muncie  engine  which  was  taken  after 
the  engine  had  been  operating  on  low  load.  The  bulb  had  not 
become  thoroughly  hot  on  the  resumption  of  full  load.  As  a 
result  of  the  fairly  cold  bulb,  the  dead-center  was  passed  before 
ignition  actually  took  place.  The  compression  line  at  dead- 
center  reached  the  point  "a."  Because  of  the  cooling  water 
absorbing  part  of  the  heat  of  compression,  as  well  as  because 
of  leaky  piston  rings,  the  compression  dropped  to  "c,"  practically 
at  dead-center  or  a  few  degrees  beyond  center.  The  explosion 
occurred  at  this  point  "c, "  reaching  to  the  point  "b"  where  the 
piston  was  fairly  well  advanced  in  the  power  stroke.  This  con- 
dition is  very  likely  to  exist  in  any  engine  that  has  been  operating 
at  a  low  load  and  has  a  heavy  load  suddenly  thrown  onto  it. 

Figure  347  shows  a  card  from  a  Mietz  and  Weiss  engine.     This 


AIR  STARTING  SYSTEMS 


445 


engine  carries  a  much  lower  compression  pressure,  about  90 
pounds,  and  the  card  here  shown  is  a  fairly  representative  one 
when  such  pressures  are  used.  The  fact  that  an  oil  engine  does 
operate  satisfactorily  with  such  a  low  compression  pressure  proves 
that  the  time  element,  as  well  as  the  temperature  range,  influences 
the  ignition  of  the  fuel  charge.  In  the  Mietz  and  Weiss  engine 
the  fuel  is  injected  very  early  in  the  compression  stroke;  this 
allows  ample  time  for  the  oil  to  distil  or  vaporize  at  a  compara- 


Scale  120  Ibs. 


Spring  Scale  200  Ibs. 


FIG.  346. — Muncie  oil  engine. 


FI.G.  347. — -M.  and  W.  oil  engines. 


tively  low  temperature.  The  objection  to  this  low  pressure  is 
the  liability  of  the  fuel  not  igniting  in  case  there  is  any  leak 
around  the  piston,  which  would  produce  a  reduction  of  the 
already  low  compression  pressure. 

Figures  348  and  349  are  cards  taken  from  the  air  compressor  of 
the  Primm  oil  engine.  The  rear  of  the  cylinder  was  used  as 
the  air  compressor.  Figure  348  was  taken  from  the  engine  when 
it  was  of  the  three-ported  design.  In  this  construction  the  piston 


Scale  18  Ibs. 


Scale  18  Ibs. 


FIG.  348. 


FIG.  349. 


uncovered  the  air-intake  port.  This  card  shows  that  the  piston 
on  the  power  stroke  created  a  suction  in  the  air  compartment 
until  about  25  degrees  from  dead-center.  The  suction  pressure 
was  around  8  pounds  absolute  or  7  pounds  below  atmospheric, 
while  the  maximum  compression  reached  8  pounds  gage.  Figure 
349  is  from  the  engine  after  being  equipped  with  an  automatic  air- 
intake  valve.  It  is  apparent  that  the  suction  pressure  is  slightly 
below  atmospheric  save  at  the  point  "  a. "  The  cause  of  this  por- 
tion of  the  suction  line  being  above  the  atmospheric  line  is  doubt- 
less the  blowing  back  of  the  engine  exhaust  gases  through  the  air 
discharge  ports.  From  these  cards  it  would  appear  that  the  power 
requirements  of  the  air  compressor  on  a  three-ported  engine  are 


446  OIL  ENGINES 

practically  twice  that  demanded  by  an  engine  using  an  auto- 
matic air-intake  valve. 

General. — In  the  operation  of  a  low-compression  oil  engine 
the  operator  must  put  aside  any  and  all  prejudices  he  may  enter- 
tain as  to  the  suitability  of  an  internal-combustion  engine.  He 
must  bear  in  mind  that  thousands  are  daily  producing  power 
at  a  total  overhead  cost  that  makes  the  oil  engine  a  successful 
competitor  of  the  Central  Station  Service.  If  he  is  possessed 
with  the  belief  that  he  is  a  "  natural-born  "  engineer  and  that  the 
oil  engine  is  an  open  book  to  him  for  his  own  good,  this  belief 
had  best  be  thrust  aside.  On  the  other  hand,  the  oil  engine  is 
not  an  unanswerable  puzzle  by  any  means.  Each  effect  has 
its  cause,  and  it  only  requires  level-headedness  and  clear  thinking 
to  enable  the  operator  to  understand  the  machine  intrusted  to 
him. 


CHAPTER  XXVI 

FUEL.     FUEL  CONSUMPTION.     OPERATION  COSTS 

INSTALLATIONS 

Fuel. — A  considerable  misapprehension  exists  among  oper- 
ating engineers  as  to  the  oils  that  are  suitable  as  fuel  in  a  low- 
pressure  oil  engine.  It  is  unfortunate  that  many  extravagant 
statements  have  been  made  concerning  the  results  obtained  with 
low-gravity  oils.  An  operator  should  understand  that  an  en- 
gine's adaptability  to  burn  the  heavy  oils  is  a  matter  that  must 
be  determined  by  a  test  on  the  particular  engine  in  which  he  is 
interested.  It  may  be  safely  stated  that  an  expert  can  secure 
satisfactory  operation  regardless  of  the  character  of  the  fuel, 
providing  the  load  be  maintained  at  a  constant  value.  The  aver- 
age operator,  however,  will  find  that  the  oils  having  a  gravity 
lower  than  24°  Baume  will  give  trouble.  In  the  oil  districts 
of  the  Southwest  the  low-pressure  engine  is  handling  pumping 
plants  and  is  burning  the  heavy  crude  oil  to  the  entire  satisfaction 
of  all  concerned.  These  engines  are  operating  on  a  constant  load, 
and  the  smoky  exhaust,  that  invariably  accompanies  the  use  of 
this  heavy  oil,  is  not  objectionable  in  such  isolated  plants.  In 
most  installations,  such  as  a  light  or  an  industrial  plant,  the  load 
is  far  from  being  constant.  On  a  varying  load  the  ignition  device 
will  not  maintain  a  temperature  sufficiently  high  to  burn  all 
the  heavy  "  uncracked  "  particles  of  oil.  The  speed  will  be  erratic, 
and  the  performance  entirely  unsatisfactory.  Furthermore,  such 
plants  are  usually  wedged  in  among  other  factories  or  mercantile 
establishments  where  the  disagreeable  features  of  a  smoky  ex- 
haust will  not  be  tolerated. 

Though  the  above  statements  concerning  the  operation  on  low- 
gravity  fuels  may  be  accepted  as  facts,  it  is  not  actually  the  oil's 
gravity  that  makes  it  objectionable,  but  rather  it  is  its  character- 
istics that  determine  its  usefulness.  Regardless  of  its  gravity,  an 
oil  must  not  contain  much  coke  or  dirt;  neither  must  it  hold  any 
large  degree  of  sulphur  or  water.  Since  practically  all  low- 
gravity  oils  do  contain  a  considerable  percentage  of  coke  and  dirt, 
the  gravity  is  usually  taken  as  an  indication  of  an  oil's  suitability. 
As  can  be  readily  seen,  the  dirt  and  coke  gives  off  no  heat  and  is 

447 


448  OIL  ENGINES 

useless  in  an  engine  cylinder.  Both  settle  on  the  combustion 
chamber  walls  in  a  hard,  thick  scale,  which  is  commonly  called 
carbon.  Filling  up  the  hot  bulb,  it  reduces  the  capacity  of 
the  bulb  and  cuts  down  the  engine's  output.  Since  it  absorbs  a 
large  amount  of  heat,  it  remains  incandescent  and  causes  pre- 
ignition  by  igniting  the  fuel  charge  early  in  the  compression 
stroke.  Frequently,  settling  on  the  cylinder  walls,  it  reveals 
itself  in  piston  cutting  and  cylinder  scoring.  The  sulphur  unites 
with  the  water,  and  the  resultant  acid  corrodes  the  cylinder. 
The  water  must  be  evaporated  and  raised  to  the  temperature  of 
the  burning  fuel  charge.  This  requires  heat;  thus  not  only  is 
the  temperature  of  combustion  lowered,  but  heat  is  abstracted. 
This  results  in  an  impaired  efficiency.  The  water  enters  the 
combustion  chamber  along  with  the  fuel  particles;  intermingling 
with  the  particles  of  oil,  it  chills  the  fuel  charge  with  a  consequent 
delay  in  the  process  of  vaporization  and  combustion. 

Since  these  objectionable  characteristics  are  possessed  by  prac- 
tically all  oils  lower  than  24°  Baume  having  an  asphaltum  base, 
the  average  plant  will  do  well  to  avoid  the  use  of  oils  heavier 
than  this  gravity.  As  a  guide  to  purchasers  of  fuel  oil  for  low- 
pressure  engines,  the  following  specifications  are  worthy  of 
attention. 

Specifications.  Fuel  Oil  for  Low-pressure  Oil  .Engines.— 
The  oil  purchased  is  to  be  either  crude  oil,  fuel  oil  or  distillate 
oil,  with  a  gravity  not  lower  than  24°  Baume,  gravity  to 
be  tested  at  a  temperature  of  60°  Fahrenheit.  The  oil  shall 
not  contain  more  than  one-half  of  one  (.5)  per  cent,  of  sulphur; 
not  more  than  eight- tenths  of  one  (.8)  per  cent,  of  water;  and 
not  to  exceed  six  (6)  per  cent,  of  coke  or  dirt.  Flash  point  below 
275°  Fahrenheit,  open  cup,  and  not  lower  than  160°  Fahr- 
enheit. When  subjected  to  fractional  distillation,  at  least  fifty 
(50)  per  cent,  shall  distil  over  at  a  temperature  below  680° 
Fahrenheit.  The  lower  heat  value  shall  not  be  less  than  18,000 
B.t.u.  per  pound.  For  engines  above  50  h.p.  these  specifications 
will  secure  a  suitable  fuel.  For  smaller  powered  engines  opera- 
ting less  than  twelve  hours  daily,  the  best  fuel  is  a  distillate  from 
32°  Baume  to  38°  Baume*.  Fuels  of  this  gravity  are  commonly 
marketed  under  refinery  trade  names,  such  as,  Staroil;  B.  Solar 
Oil;  Oriental  Distillate,  etc.  These  oils  usually  have  a  yellow- 
greenish  color,  though  some  approach  the  color  of  kerosene.  It 
is  the  best  for  medium-powered  plants  as  it  is  heavy  enough  to 


FUEL  CONSUMPTION 


449 


be  used  without  a  great  amount  of  preignition,  and  yet  of  high 
enough  gravity  to  vaporize  and  ignite  at  a  fairly  low  bulb 
temperature. 

The  very  small  units,  ranging  from  10  to  20  h.p.,  work 
best  on  kerosene,  around  44°  Baume  gravity.  These  engines 
are  seldom  loaded  up  to  full  capacity,  and  so  there  is  little  likeli- 
hood of  serious  preignition,  which  will  occur  on  full  load  with 
kerosene.  The  kerosene  vaporizes  very  readily,  and  the  bulb  can 
run  at  a  low  temperature.  This  is  an  advantage  as  the  small 
engines  usually  are  started  and  stopped  several  times  each  day. 
It  might  be  well  to  call  attention  to  the  trouble  that  is  experienced 
in  large  engines  pulling  heavy  loads  while  using  kerosene.  In- 
vestigations covering  over  one  hundred  installations  where 
kerosene  had  been  burned  revealed  that  in  every  instance  severe 
cylinder  cutting  occurred.  It  is  impossible  to  definitely  deter- 
mine why  this  condition  should  exist.  In  a  number  of  engines 
36°  Baume  distillate  had  been  used  with  entire  satisfaction, 
but  on  changing  to  44°  Baume  kerosene  cylinder  cutting 
immediately  became  apparent. 

The  various  make  engines  show  quite  different  operating  char- 
acteristics with  oils  of  practically  the  same  gravity.  Table  XVI 
is  the  result  of  a  series  of  tests  on  a  25  h.p.  Fairbanks- 
Morse  Type  Y  engine.  This  engine  has  a  hot  combustion  cham- 
ber and  operates  without  water  injection. 


TABLE  XVI. — BEHAVIOR  OF  A  LOW-PRESSURE  ENGINE  ON  VARIOUS  FUELS 
Make  of  Engine. — Fairbanks-Morse  Type  Y,  25  H.p. 


Fuel 

Characteristics 

Engine  behavior 

Texas  Crude. . 


Texas  Fuel  Oil . 
Okla.  Distillate. 

Kerosene 

^    kerosene; 
gasolene 


Asphaltum  base;  j  Speed   slightly   below   normal. 
24°    Baume;    .5     haust  smoky. 
per  cent,  sulphur 


Ex- 


32C 
36C 


Baume . 
Baume . 


44°  Baume 


Speed  normal.    Exhaust  almost  clear. 

Speed  normal.  Exhaust  clear.  Slight 
preignition  at  Full  Load. 

Speed  normal.  Exhaust  clear.  Pre- 
ignition at  Full  Load. 

Speed  above  normal.  Preignition  at 
all  loads  Above  Half  Rating;  very 
violent  at  Full  Load.  Engine  had 
a  tendency  to  "hunt." 


2(1 


450 


OIL  ENGINES 


Table  XVII  covers  the  behavior  of  a  50  h.p.  Bessemer  oil 
engine  using  water  injection. 

TABLE  XVII. — BEHAVIOR  OF  A  LOW-PRESSURE  OIL  ENGINE  ON  VARIOUS 

FUELS 

Make  of  Engine. — Bessemer,  50  H.p. 


Fuel 


Characteristics 


Engine  behavior 


Texas  Crude  
Texas  Fuel  Oil  ... 
Kerosene  

Asphaltum  base; 
24°  Baume 
32°  Baume"  

46°  Baume  

Speed    normal.         Exhaust    smoky. 
Water  injection  reduced  from  normal. 
Speed     normal.     Exhaust     slightly 
dark. 
Speed  normal.     Water  injection  was 

Gasolene 

62°  Baume 

increased.     Slight    preignitions    at 
Full  Load.     Exhaust  clear. 
Speed  a  trifle  above  normal      \Vater 

injection  increased  which  killed  the 
preignitions.     Exhaust  clear. 

These  tests,  while  not  entirely  conclusive,  indicate  that  an  oil 
with  a  higher  gravity  can  be  burned  without  preignition  in  a 
water-injection  engine  than  in  a  "dry"  engine.  Due  to  this 
comparative  absence  of  preignition  in  the  water-injection  en- 
gine, there  is  also  less  tendency  to  "hunt."  On  the  heavier  oils 
both  engines  displayed  a  smoky  exhaust.  The  exhaust  of  the 
water-injection  engine  always  has  a  dark  color  accompanied  by 
an  oily  or  tar-like  fog,  which  is,  of  course,  a  result  of  a  com- 
bination of  the  steam  and  heavy  hydrocarbons.  So  objection- 
able is  this  oily  exhalation  that  it  is  never  advisable  to  run  a 
stream  of  water  into  the  exhaust  line,  even  though  this  does 
serve  to  deaden  the  noise. 

Fuel  Storage. — It  is  seldom  profitable  to  purchase  oil  in  barrel 
lots  when  the  yearly  consumption  exceeds  8000  gallons.  With 
an  annual  demand  beyond  this  figure  the  difference  in  the  car- 
load and  barrel  prices  will  pay  for  a  storage  tank.  When  the 
yearly  requirements  are  less  than  two  tank  cars,  the  best  storage 
is  the  vertical  corrugated  steel  tank  made  of  No.  16  gage  galva- 
nized sheets.  These  tanks  are  not  costly  and  serve  their  purpose 
admirably.  If  leaks  develop  at  the  rivets,  a  little  soap  will  seal 
the  openings  until  the  seam  can  be  soldered  when  the  tank  is 
emptied.  There  is  no  danger  of  an  explosion  when  soldering, 
for,  unlike  a  gasolene  tank,  the  small  amount  of  vapor  fumes 


FUEL  CONSUMPTION 


451 


speedily  dispel  after  the  tank  cover  is  removed.  Red  lead  is 
useless  as  a  temporary  seal  since  the  oil  causes  the  lead  to  thin 
and  flow.  In  the  Northern  states  a  cypress  storage  tank  can  be 
employed  with  success.  The  cypress  tank  is  lower  in  price  than 
is  the  steel  one;  in  the  Southern  states  the  oil  evaporation  from 
a  wood  tank  is  too  excessive  to  justify  its  utilization.  With 
the  larger  units,  ranging  from  50  h.p.  upward,  the  choice  of 
storage  lies  between  the  horizontal  steel  tank,  constructed  of 
boiler  plate,  and  the  vertical  concrete  tank,  in  the  majority 
of  installations  the  steel  tank  is  more  advisable  since  it  is  difficult 
to  secure  the  services  of  a  concrete  contractor  who  is  able  to  con- 
struct a  leak-proof  concrete  tank. 


0.4 1— 


0.6 


S 

5  1.0 


1.2 


1.4 


20 


40 


100 


120 


Brake  H.P. 
FIG.  350.— Test  16  X  20  -  85  H.P.  Bessemer  oil  engine. 


Fuel  Consumption. — An  average  of  the  guarantees  of  various 
builders  of  low-pressure  oil  engines  gives  the  following  values  for 
fuel  consumption: 

Full  load  Three-quarters  load          One-half  load 

.65  Ib.  .68  Ib.  1.00  Ib. 

These  figurejs  are  based  on  the  use  of  fuels  from  32°  to  44°  Baume. 
On  factory  tests  or  on  tests  conducted  by  an  engineer  who  is 
thoroughly  conversant  with  the  peculiarities  of  the  engine  tested, 
these  values  can  usually  be  more  than  equaled.  However, 


452 


OIL  ENGINES 


in  actual  operation,   the  engineer   cannot   hope  to  better  the 
builder's  guarantee;  indeed,  he  is  fortunate  if  he  equals  it. 

Figure  350  is  the  result  of  a  factory  test  run  on  a  Bessemer  oil 
engine  No.  16668  of  85h.p.  rating.  The  standard  guarantee  of 
this  concern  is  Jfo  pint  or  from  .6  pound  to  .7  pound,  dependent 
on  the  weight  of  the  oil  per  gallon.  The  test  curve  shows  the 
full-load  fuel  consumption  to  have  been  .57  pound,  while  the  half- 
load  value  was  .63  pound.  This  half-load  fuel  consumption  is 
rather  remarkable.  Ordinarily,  the  net  mechanical  efficiency 


1.6 


1.4 


1.2 


W 
P 

o  0.8 

*  0.6 

0.4 

0.2 


0  J4  !i  £  1 

Engine  Load  Rating 

FIG.  351. — Test  on  85  H.P.  Bessemer  oil  engine. 

of  a  two-cycle  low-pressure  engine  is  around  85  per  cent,  at  full 
load  and  approximately  70  per  cent,  at  half  load.  Naturally  it 
would  seem  that  at  half  load  the  fuel  consumption  must  be  at 
least  8J"7o  of  the  full-load  result.  The  half-load  efficiency  would 
be  still  less,  due  to  the  lower  cylinder  temperature.  That  the 
fuel  consumptions,  in  this  case,  are  practically  identical  can 
evidently  be  attributed  to  the  higher  thermal  efficiency  at  half 
load ;  the  oil  vapor  and  air  mixture  was  leaner  than  at  full  load — 
it  has  been  proved  many  times  that  with  a  lean  mixture  the 
thermal  efficiency  is  higher  than  with  a  rich  mixture. 


FUEL  CONSUMPTION 


453 


Figure  351  shows  the  results  of  a  test  on  an  85  h.p.  Bes- 
semer engine,  installed  in  a  cotton  gin  and  using  Texas  distillate 
of  36°  Baume.  The  full-load  value  closely  approximated  the 
factory  test  in  Fig.  350;  the  increased  fuel  consumption  at  the 
lower  loads  is  due,  no  doubt,  to  misadjustments  in  the  fuel 
pump  and  injector  nozzle,  since  the  engine  had  been  operated 
one  season  by  an  inexperienced  engineer.  Even  with  this  handi- 
cap the  results  are  surprisingly  good. 


f 

2100 
1800  ^ 

0 

i 
1500S. 

k. 

O 

1200^ 

c 

§ 

1 
BOO1- 

300 

\ 



J 

^ 

-  —  ' 

fc 

/[ 

.c 

m    1  1   *"  ififl 

/ 

\ 

i 

V 

s- 

1 

0 

^ 

\ 

|7^/ 

\ 

(sN^ 

'     W 

u 

<U        :§ 
Q. 

S 

c  OR  "5  Iflfl 

2 

~7 

T 

S.    ° 

Kc- 

-^     Sf 

^ 

~>    = 

S 

. 

•s 

CX. 

TN 

4 

p 

E 

p 

f/p 

^' 

1 

S^ 

r 

w 

?* 

i 

0              \ 

1          1 

Per  Cent,  Load 
FIG.  352. — Test  on  50  H.P.  Fairbanks-Morse  vertical  type  Y  oil  engine. 

Figure  352  is  a  test  on  a  50  h.p.  Fairbanks-Morse  vertical 
Type  Y  engine.  The  engine  was  of  the  single- cylinder  design 
and  was  installed  in  a  combination  electric  light  and  flour  mill 
plant.  After  the  engine  had  been  in  service  for  some  time,  the 
question  as  to  its  fuel  consumption  in  actual  operation  was  raised. t 
A  test,  consisting  of  three  one-hour  runs  at  the  various  loads,  was 
conducted.  The  fuel  was  carefully  weighed,  while  the  tempera- 
ture of  the  cooling  water  was  maintained  as  constant  as  possible 
by  operating  the  inlet  valve;  the  actual  amount  of  cooling  water 
used  was  measured  by  two  tanks  of  known  value.  The  engine  car- 
ried a  10  per  cent,  overload  with  ease,  but  at  25  per  cent,  overload 


454 


OIL  ENGINES 


1.6 


1.4 


1.2 


" 


0.8 


I 


,§0.6 
a 


0.4 


0.2 


o         u 

Engine  Rating 

FIG.  353. — Test  on  Fetter  16  H.P. 
oil  engine. 


1.0 


3 
O 

=  0.8 

c* 


0.6 


gO.2 


Engine  Load 

FIG.  354. — Test  'on  type  DH  De  La- 
Vergne  Co.  60  HP. 


40  50  60  70 

Developed  Horse  Power 


90          100         119 


FIG.  355. — Fuel  consumption  curve  Buckeye-Barrett  75  H.P.  oil  engine. 


FUEL  CONSUMPTION  455 

the  exhaust  became  very  smoky,  showing  that  part  of  the  fuel 
was  not  being  consumed.  The  engine  labored  considerably 
and  lost  speed  slightly.  Since  no  oil  engine  should  be  expected 
to  carry  more  than  a  10  per  cent,  overload,  the  behavior  on  the 
25  per  cent,  overload  is  not  open  to  criticism. 

The  fuel  was  a  38°  Baume  distillate  weighing  6.94  pounds 
per  gallon.  The  builder's  guarantee  of  fuel  consumption  at  full 
load  was  .694  pound.  This  guarantee  was  more  than  fulfilled. 
The  efficiencies  at  the  lower  loads  were  also  good. 

Figure  353  covers  tests  on  a  16  h.p.  Fetter  oil  engine. 
This  engine  was  built  at  Yoevil,  England,  and  was  imported  for 
experimental  purposes  by  a  firm  which  was  entering  the  low- 
pressure  engine  field.  Curve  a  covers  the  test  using  26°  Baume 
Peruvian  crude  oil;  b  covers  28°  fuel  oil,  while  c  covers  the  use 
of  42.5°  distillate  or  stove  oil. 

Figure  354  covers  tests  on  a  60  h.p.  De  La  Vergne  Type  D.H. 
low-pressure  oil  engine.  These  were  factory  tests  and  are  much 
lower  than  the  company's  guarantee.  In  fact,  they  approach 
the  performance  of  the  Diesel  engine. 

Figure  355  is  the  result  of  a  test  on  a  75  h.p.  Buckeye-Barrett 
oil  engine  using  Lima  Ohio  crude.  These  results  are  quite 
representative  of  low-pressure  engine  practice. 

Operation  Costs. — The  fuel  consumption  in  actual  operation 
is  much  greater  than  the  values  obtained  on  a  test.  In  the  latter 
case  all  conditions  are  well-nigh  perfect,  whereas  in  ordinary  opera- 
tion many  things  serve  to  preclude  ideal  results.  The  engineer 
should  be  guided  by  his  judgment  in  determining  whether 
he  is  obtaining  fair  efficiency,  rather  than  by  comparison  with 
factory  tests.  Even  though  the  efficiency  be  considerably  lower 
than  that  reported  by  the  testing  engineers,  the  operator  should 
not  feel  that  the  engine  is  not  giving  satisfactory  service.  This, 
of  course,  applies  only  to  plants  where  a  reasonable  amount  of 
attention  is  given  the  various  engine  parts  and  necessary  adjust- 
ments made. 

Table  XVIII  covers  a  monthly  report  on  a  small  combined 
water  and  light  plant.  In  this  plant  a  50  h.p.  low-pressure  oil 
engine  was  belted  to  an  alternator  and  a  waterworks  pump. 
Even  though  the  engine  was  not  carrying  its  rated  load,  the 
fuel  cost  was  reasonable.  The  lubricating  oil  consumption  was 
somewhat  high,  but  this  was  evidently  due  to  the  lack  of  a  filter. 
It  is  in  such  plants  as  this  one  that  the  low-pressure  engine  finds 


456  OIL  ENGINES 

TABLE  XVIII. — OPERATION  COSTS  OF  COMBINED  WATER  AND  ELECTRIC 

LIGHT  PLANT 

Engine 50  h.p.,  vertical   low-pressure 

Generator 30  kv.a.  alternator 

Pump 6  X 10  in.  duplex  power  pump 

Total  kw.-hr.  during  month 2920 

Total  hours  in  operation 182 

Average  kilowatts  per  hour 16. 15 

Water  pumper  per  month,  gallons 1,820,000 

Pumping  head,  feet 140 

Electrical  h.p.,  figuring  90  per  cent,  generator  efficiency 4350 

Water  h.p.,  assuming  50  per  cent,  pump  efficiency 1786 

Total  brake  horsepower 6136 

Distillate  oil  used,  gallons 840 

Cost  of  fuel  at  4>£  cents  per  gal $37 .80 

Cost  of  lubricating  oil  (20  gal.  at  35  cents) 5 . 00 

Waste  and  incidentals 3 . 55 

Engineer's  wages  per  month   (one  man  used) 70. 00 

Total  operating  cost 116.35 

Total  operating  cost  per  h.p 0. 0189 

Gallons  of  fuel  oil  per  h.p.-hr 0. 135 

its  greatest  field.  Such  a  plant  could  not  exist  if  a  steam  engine 
were  used  since  the  operating  expenses  would  exceed  the  gross 
income.  In  this  plant  the  engineer's  wage  was  not  high,  but 
the  matter  of  wages  is  largely  determined  by  the  cost  of  liv- 
ing in  the  particular  locality.  This  plant  was  situated  in  a 
small  Texas  town  where  living  expenses  were  low;  the  engineer's 
salary  of  $70  probably  was  as  high  as  was  paid  to  any  workman 
in  the  town. 

While  it  is  in  the  smallwater  works  and  electric  light  plants 
that  these  engines  are  in  greatest  demand,  industrially  they  are 
meeting  the  requirements  of  low  fuel  and  maintenance  charges. 

In  those  larger  centers  where  electric  power  can  be  purchased 
for  3  cents  per  kw.-hr.,  it  is  problematical  whether  the  low- 
pressure  oil  engine  can  be  used  successfully.  In  communities 
where  electric  power  rates  range  from  5  cents  upward  and  where 
the  power  demand  is  under  100  h.p.,  the  owner  of  a  small 
manufacturing  plant  should  install  some  make  of  the  low- 
pressure  oil  engine  and  thereby  reduce  his  factory  costs.  For 
example,  a  small  100-barrel  flour  mill,  if  running  twenty-four 
hours  daily  and  producing  the  rated  capacity,  will  use  be- 
tween 600  and  700  kw.-hr.  per  day.  At  the  low  rate  of 
5  cents  per  kw.-hr.  the  power  charges  would  run  from  $30  to  $35 


FUEL  CONSUMPTION 


457 


daily.  Since  it  requires  approximately  10  h.p.-hr.  to  pro- 
duce a  barrel  of  flour,  a  50  h.p.  oil  engine  would  handle  the 
plant  with  ease,  being  able  to  operate  the  elevator  machinery 
as  well.  Such  a  unit  on  a  load  of  40  h.p.  would  not  consume 
in  excess  of  100  gallons  of  distillate  oil  per  day.  The  fuel  would 
cost  less  than  $5  per  day.  On  the  basis  of  three  hundred  working 
days  the  net  saving,  including  fuel,  lubricating  oil,  etc.,  as  well 


0.90 


0.80  .  80 


FIG.  356. — Hourly  load  and  fuel  cost,  steam  power. 

as  the  wages  of  an  operator,  is  more  than  $6000  yearly.  The  only 
argument  against  tl^e  use  of  an  oil  engine  in  such  installations  is 
the  poor  results  obtained  from  engines  erected  several  years  ago. 
During  the  last  few  years  the  improvements  in  design  have 
converted  this  type  of  engine  into  a  very  reliable  mechanism. 
Records  of  one  hundred  to  one  and  fifty  days  of  twenty-four 
hours'  service  without  a  single  stop  are  not  extraordinary. 

The  field  for  this  oil  engine  is  not  limited  to  new  installations. 
Indeed,  its  greatest  opportunity  lies  in  those  steam  power  plants 
where  the  load  is  light  during  the  major  part  of  the  day.  Often 


458 


OIL  ENGINES 


it  is  possible  to  install  an  oil  engine  to  care  for  the  light  loads, 
relying  on  the  steam  unit  to  meet  the  demands  of  the  peak  load 
which  are  beyond  the  capacity  of  the  oil  engine.  An  example  of 
such  a  combined  steam-oil  engine  plant  is  the  Municipal  Power 
Plant  at  Pala  Alto,  California. 

The  records  of  a  somewhat  similar  plant,   although  much 
smaller,  are  given  below.     This  plant  originally  contained  a  small 

1.20 


the  Load  on  the  Steam  Engine 


0.10      10 


FIG.    357. — Hourly    load    and    fuel    costs,    using    combined    oil    and    steam 

engine  units. 

Corliss  and  a  high-speed  engine,  and  two  tubular  boilers.  The 
output  of  the  plant  was  used  in  lighting  the  municipality  and  in 
pumping  water. 

Figure  356  shows  the  hourly  load  carried  as  well  as  the  fuel 
costs.  This  excessive  fuel  expense  was  instrumental  in  the  in- 
stalling of  a  60  h.p.  low-pressure  oil  engine  which,  with  the  boiler 
alterations,  cost  $4200.  In  order  to  even  up  the  load,  the  hours 
of  pumping  were  slightly  changed. 

The  plan  of  operation  is  to  have  the  oil  engine  handle  the  load 


FUEL  CONSUMPTION 


459 


from  midnight  until  7  P.  M.  the  next  morning.  At  that  hour  the 
steam  boilers,  which  have  partially  maintained  their  pressure  all 
day,  are  fired  up,  using  fuel  oil.  The  corliss  engine  then  carries 
that  part  of  the  evening  peak  load  which  exceeds  the  capacity 
of  the  oil  engine.  Figure  357  gives  the  hourly  load  and  hourly 
fuel  costs  while  operating  under  this  arrangement.  The  fuel 
expense  during  the  peak  load  is  high  since  fuel  oil  is  burned 
under  the  boilers.  The  daily  expenditure  under  the  old  and  the 
new  plan  is  as  follows: 

TABLE  XIX 


Old  steam 
plant 

Steam  and 
oil 

Fuel: 
Coal  at  $1.80  per  ton  

$11  60 

Oil  at  $  .03  per  gal  

$7  25 

Labor  : 
2  engineers  at  $72.00  per  month  ...            •  •     \ 

8.80 

2  firemen  at  $60.00  per  month                           / 

2  engineers  at  $80.00  per  month  1 

1  fireman  at  $60.00  per  month  / 

7.33 

Total  

$20  40 

$14  58 

Net  saving  per  day  

5  82 

Net  saving  per  year  

$2124  30 

Conclusion. — The  low-compression  oil  engine  does  possess 
merit.  It  has  a  field  of  usefulness  that  is  gradually  increasing 
in  extent.  Its  competitors  are  the  Diesel  and  semi-Diesel  en- 
gines, although  the  fields  of  these  three  types  do  not  overlap  to 
any  marked  extent.  The  operating  costs  just  discussed,  when 
taken  in  conjunction  with  the  Diesel  costs  in  Chapter  XVI, 
afford  a  means  of  comparing  the  values  of  the  two  types  of  oil 
engines  in  respect  to  their  efficiency  as  heat-converters.  It 
must  be  remembered  that  operating  costs  are  by  no  means  total 
costs;  consequently  in  many  plants  where  the  Diesel  oil  engines 
of  low  powers  are  installed,  low-compression  engines  would  prove 
far  more  economical  in  respect  to  total  costs  per  horsepower  hour. 


INDEX 


Diesel  Engine  Index \ Pages  461  to  468 

Semi-Diesel  Engine  Index Page9  468  to  469 

Low-Compression  Engine  Index Pages  469  to  472 

Diesel  Engine  Index 


Adjustable  injection  air  pressure,  156-157 

main  bearings,  44-45 
Admission  valves  (see  Valves),  93-123 
Air, 

bottles,  206-207 

compression  systems  (see  Compressors), 

195-208 
pipe,  206 
pressure  for  injection  valves,  207-208 

regulation,  156-157,  207,  208 
Aligning  of  bearings,  51 
Allis-Chalmers  Diesel,  19 
admission  valves,  112 
air  compressor,  204-205 
bearings,  48 
connecting-rod,  58-59 
cylinder,  85 
head,  85 

exhaust  valve,  112 
fuel  pump,  171-172 
governor,  188 

indicator  cards,  273,  274,  275 
injection  valve,  145-147 
main  bearing,  48 
piston,  69-70 
valves,  admission  and  exhaust,  112 

fuel  injection,  145-147 
American  Diesel,  13-15 
admission  valves,  94 
bearings,  44 
connecting-rod,  57-58 
cylinder,  79 

head,  79-80 
exhaust  valve,  95 
fuel  consumption,  258-260 

pump,  159-161 
governor,  183 
injection  valve,  131-134 
main  bearings,  44 
piston,  66-67 
production  costs,  263 
valves,  admission  and  exhaust/94-96 
adjustments,  96-97 
timing,  97-98 
injection,  131-134 


Babbitting  a  bearing,  52-54 
Barber  producer-gas  engine,  1 
Bearings,  main,  44 

adjustable,  for  vertical  engine,  44 

for  horizontal  engines,  45 
aligning  of,  51 
Allis-Chalmers,  48 
American  Diesel,  44 
babbitting  of,  52-54 
Busch-Sulzer,  49-50 
clearances  of,  55 
De  La  Vergne,  50 
hot,  54-55 
McEwen,  50 
National  Transit,  46 
Snow,  46-47 
two-cycle  engine,  of,  56 
two-piece,  48-49 

Brayton's  constant  pressure  engine,  5 
Busch-Sulzer  Diesel,  15 
admission  valves,  98 
air  compressor,  198-199 
bearings,  main,  49-50 
connecting-rod,  61 
cylinder,  82 
head,  82 

exhaust  valve,  98 
fuel  consumption,  251,  254,  257,  258 

pump,  161-163 
governor,  185-186 
guarantee  of  fuel  consumption,  251 
injection  valve,  134-139 
adjustments,  136-137 
servomotor,  137-138 
piston,  67-68 

valves,  admission  and  exhaust,  98-101 
cam  levers,  99-137 
camshaft  layout,  100 
lever  roller  clearances,  100 
timing,  99 
injection,  134-139 


Camshafts,  94 

Allis-Chalmers,  112 


461 


462 


INDEX 


Camshafts,  American  Diesel,  Fig.  7,  94 
Busch-Sulzer,  99-100 
De  La  Vergne,  115 
McEwen,  108 
Mclntosh  &  Seymour,  102 
Mclntosh  &  Seymour  Marine,  116 
National  Transit,  110-111 
National  Transit  1918  Model,  28,  112 
Nelseco  Marine,  118-119 
Snow,  28,  106 

Center-line,  establishing  engine,  33 
Centering  engine  shaft,  40-41 
Circulating  pumps,  57 

water  (see  Cooling  systems). 
Clearances,  bearing,  55 
crank-pin,  63 
piston,  65 
valve  cam,  of 

American  Diesel,  96 
Busch-Sulzer,  99 
McEwen,  108 
Mclntosh  &  Seymour,  103 
National  Transit,  29 
Snow  Diesel,  107 
Clerk's  two-cycle  engine,  5 
Combustion,  232-234 
Compressors,  air,  195-208 
built-in,  197-205 

Allis-Chalmers,  204-205 

Busch-Sulzer,  198-199 

McEwen,  202-203 

Mclntosh  &  Seymour,  200-201 

Mclntosh  &  Seymour  Marine,  199- 

200 

National  Transit.  203 
Snow.  201-202 
Standard  Fuel  Oil,  203-204 
independent,  190 
lubrication  of,  206 
pressure,  54 
stages,  196 
suction,  206 
valves,  205-206 

Connecting-rods,  big-end  bearing  of,  62-63 
designs,  57 

Allis-Chalmers,  58-59 
American  Diesel,  57-58 
Busch-Sulzer,  61 
De  La  Vergne,  62 
McEwen,  60 

Mclntosh  &  Seymour,  60 
National  Transit,  60-61 
Nelseco,  62 
Snow,  59 

pin  clearances  of,  63 
Constant  pressure  engine,  Brayton's,  5 
Cooling  water  (see  Cooling    systems),  209- 

223 

temperature  of,  211,  223 

Cooling  water  systems,  209-223 

bad  water  in,  220-221 


Cooling  water  systems,  circulating  pumps, 

220 

sediment  in,  221 
tanks  and  towers  for,  214 
towers,  cooling,  for,  216-220 
types  of,  212-214 

closed  system,  212 

open  system,  213-214 
water  pipe  for,  214 

required  in,  210 
Costs,  production, 

Diesel,  260-264 

gas  engine,  72 

producer  gas,  72 

steam,  74 

turbine,  73 
Crank-pin  bearings,  63 

clearances,  63 
Crankshafts,  fractured,  5G 
Crosshead  piston,  65 
Cycle  of  events,  Diesel,  10 

two-cycle  Diesel,  13 
Cylinders,  79 
designs  of, 

Allis-Chalmers,  85 

American  Diesel,  79 

Busch-Sulzer,  82 

De  La  Vergne,  Fig.  15,  83 

Fulton  Iron  Works,  82-83 

horizontal,  83 

McEwen,  Fig.  14 

Mclntosh  &  Seymour,  82-83 

National  Transit,  86 

Snow,  Fig.  11,  83 

Standard  Fuel  Oil,  80-81 
erecting  of,  39-40 

fractured,  86 

liner  replacement,  87-88 

reboring  of,  87 

scored,  86-87 

Cylinder  head,  fractured,  90-91 
joints,  88-89 
repair  of,  91-92 
studs,  89-90 
Cylinder  heads,  designs  of, 

Allis-Chalmers,  85 

American  Diesel,  79-80 

Busch-Sulzer,  82 

De  La  Vergne,  83 

horizontal  engines,  83 

McEwen,  85 

Mclntosh  &  Seymour,  82-83 

National  Transit,  86 

Snow,  83 

Standard  Fuel  Oil,  81-82 

D 

De  La  Vergne  Diesel,  22 
bearings,  50 
connecting-rod,  62 


INDEX 


463 


De  La   Vergne   Diesel,  cylinder,  Fig.  15,  83 

head,  86 
fuel  consumption,  251 

pump,  173 
governor,  46 
guarantees,  fuel,  251 
main  bearing,  50 

valves,  admission  and  exhaust,  115 
valve  timing,  115 
Diesel  engine,  The,  7-280 

American  Manufacturers  of, 
Allis-Chalmers  Co.,  19 
American   Diesel  Engine  Co.  (Am.), 

13-15 
Busch-Sulzer  Bros.  D.  E.  Co.  (type 

B),  15 
De  La  Vergne  Machine  Co.  (F.D.), 

22 

Fulton  Iron  Works,  82 
Fulton  Machine  Co.,  31 
Lyons-Atlas  Co.  (Atlas),  31 
McEwen  Bros.,  20-21 
Mclntosh  &  Seymour   Co.,  15-18,  28 
Midwest  Engine  Co.  (Werkspoor),  27 
National  Transit  P.  &  M.  Co.,  20 
New     London     Ship     &    Eng.    Co. 

(Nelseco),  28 
New  York  Shipbuilding  &  Eng.  Co., 

(Werkspoor),  27 
Nobel  Bros.,  25 
Nordberg  Co.  (Corels),  31 
Pacific  Skandia  Co.  (Werkspoor),  27 
Snow  Pump  Works,  18 
Southwark  Foundry  &  Machine  Co., 

22-25 

Standard  Fuel  Oil  Engine  Co.,  25 
Worthington  Pump  &  Machine  Corp. 

(Snow),  18 
cycle  of  events  of,  10 
marine,  9 

Mclntosh  &  Seymour,  28 

Nelseco,  28 

New  York  Shipbuilding  &  Eng.  Co., 

28 

Nobel  Bros.,  25 
Pacific  Skandia,  28 
Southwark-Harris,  22-25 
Werkspoor,  26 
schematic  layout  of,  10 
two-stroke-cycle,  22 
schematic  layout  of,  13 
Southwark-Harris,  22-24 
Standard  Fuel  Oil,  25 
Distiller,  exhaust,  222-223 


Efficiency  of  the  Diesel  (see  Fuel  consump- 
tion). 
Engine  center  line,  33 

cylinder,  erection  of,  39—40 


Engine  erection,  32-43 

establishing  center-line  of,  33,  40 
foundation,  bolts,  35 
excavation  for,  32-33 
insufficient,  33-34 
material  for,  34-35 
Engine  frame,  installation  of,  37 

leveling  of,  38 
template,  34 
Engines,  oil, 

Brayton's,  5 

Diesel  (see  Diesel  eng ine) . 
Hornsby-Ackroyd,  6 
Low-compression     (see     Low-compres- 
sion section  of  index). 
Semi-Diesel  (see  Semi-Diesel  section  of 

index). 

Erection  of  engine,  32-34 
Exhaust  distiller,  222-223 

valves  (see  Valves),  93-123 


Foundation,  bolts,  35 

excavation  for,  32-33 
insufficient,  33-34 
material  for,  34-35 
vibration  of,  36-37 
Fractured  crankshaft,  56 

cylinders,  86 
Frame,  installation  of  engine,  37-38 

leveling  of,  38 

Fuel  consumption,  guarantees, 
Busch-Sulzer,  251 
De  La  Vergne,  251 
Fulton  Machine  Co.,  251 
Korting,  251 
McEwen,  251 
Mclntosh  &  Seymour,  251 
Mclntosh  &  Seymour  Marine,  251 
National  Transit,  251 
Nelseco,  251 
Snow,  251 

Standard  Fuel  Oil,  251 
operating  results,  257-260 

American  Diesel,  258,  259-260 
Busch-Sulzer,  258 
tests, 

American  Diesel,  263 

Busch-Sulzer,  255 

Korting,  254 

McEwen,  252 

Mclntosh  &  Seymour,  255-257,  259- 

260 

Snow,  252 

Standard  Fuel  Oil,  253 
Fuel  injection  valves  (see  Injection  valves.) 
Fuel  oil,  234-250 
acid  in,  244 
ash,  percentage  in,  244 
burning  point  of,  242 


464 


INDEX 


Fuel  oil,  classification  of,  234-238 

flash  point  of,  241 

gravity  of,  239 

heat  value,  239 

production  of,  235,  Table  IV 

specification,  238 

sulphur  per  cent,  in,  242 

tanks  for,  246-248 

viscosity  of,  244 

water  in,  243-244 
Fuel  pumps,  159-180 

Allis-Chalmers,  171-172 

American  Diesel,  159-161 

Busch-Sulzer,  161-163 

De  La  Vergne,  173 

McEwen,  168-170 

Mclntosh  &  Seymour,  164-166 

Mclntosh  &  Seymour  Marine,  166-168 

National  Transit,  175-176 

National  Transit  1918  Model,  176-178 

Nelseco,  173-175 

Snow,  170-171 

Standard  Fuel  Oil,  178-179 
Fulton  Iron  Works  Diesel,  83 
Fulton  Machine  Co.  Diesel,  28,  154,  251 


Gas  engines,  early, 
Barber,  1 

Beau  de  Rochas,  1 
Brayton's,  5 
Clerk's,  5 
Huyghens,  1 
Lenoir,  2 
Otto,  2 
Otto  Silent,  3 
production  costs,  264 
Gear  lubrication,  194 
Gears,  governor  shaft  (see  Governors). 
Governor  shaft  gears,  192,  194 

springs,  193-194 
Governors,  181-194 

Allis-Chalmers,  188 
American  Diesel,  183 
Busch-Sulzer,  185-186 
Jahns  System,  183-186 
McEwen,  186-188 
Mclntosh  &  Seymour,  189-193 
National  Transit,  186 
Nelseco,  173 
Snow,  186 

Standard  Fuel  Oil,  188 
Gravity  of  fuel  oil,  65 
Guarantees  of  fuel  consumption,  251 
(see  Fuel  consumption,  guarantees). 


Heads,  cylinder,  designs  of, 
Allis-Chalmers,  85 


Heads,  cylinder,  American  Diesel,  79 
Busch-Sulzer,  82 
De  La  Vergne,  83 
horizontal  Diesel,  83 
McEwen,  84,  85 
Mclntosh  &  Seymour,  83 
National  Transit,  86 
Snow,  83 

Standard  Fuel  Oil,  81 
fractured,  90 
joints,  88-89 
repair  of,  91-92 
studs,  89-90 
Heat  balances,  comparative,  270,  271 

losses,  distribution  of,  209 
Hornsby-Ackroyd  Oil  engine,  6 
Huyghens  engine,  1 

I 

Indicator  cards,  270-278 
distorted,  278 
faulty,  274-278 
rigging,  279 
typical, 

Allis-Chalmers,  273,  274,  275 
McEwen,  273 
National  Transit,  273,  275 
Standard  Fuel  Oil,  274,  276 
Injection  action,  127 
Injection  fuel  valves, 
adjustments, 

adjustable  air  pressure,  156,  199 
air  pressure,  207 
clogged  nozzle  tips,  156 
leaky  valves,  155-156 
lubrication,  155 
needle  valve,  154-155 
regrinding,  154 
timing,  156,  158 
adjustable,  157 
incorrect,  158 
classification,  129 

closed  nozzle,  130-131 
open  nozzle,  129 
designs  of,  127 

Allis-Chalmers,  145-149 
American  Diesel,  131-134 
Busch-Sulzer,  134-139 
Fulton  Machine  Co.,  154 
Korting,  144-145 
McEwen,  145-146 
Mclntosh  &  Seymour,  139-142 
Mclntosh  &  Seymour  Marine,  142 
National  Transit,  149-150 
Nelseoo,  154 
Snow,  142-144 
Standard  Fuel  Oil,  150-153 
Injection  fuel  valve  of  original  Diesel,  127 
Injection  fuel  valves  for  tar  oil,  154 
Installation,  32-48 

aligning  of  bearings,  40 


INDEX 


465 


Installation,  cylinder  erection,  39-40 
engine  frame,  37-38 
engine  template,  34 
establishing  center  line,  33 
excavation,  32-33 
foundation,  34-35 
foundation  bolts,  35 
leveling  of  frame,  38 
plant  building,  43 
shaft,  centering  of,  40- -43 
vibration,  30 


Jahns  governors,  183-186 
Joints,  cylinder  and  head, 


Korting  Dieselfuel  consumption,  251,  254 
Korting  fuel  injection  valve,  144 


Lenoir  gas  engine,  2 
Liner  replacement  cylinder,  87-88 
Logs,  plant,  268-209,  270 
Imbrication,  224-231 

amount  of,  231 

of  compressor,  206 

of  gears,  194 

oil  requirements,  229 

oil  specifications,  230 
Lubrication  systems,  224-229 

pressure  feed,  227-228 

splash,  228-229 

stream,  226 
Lyons-Atlas  (Midwest)  Diesel,  31 


M 


Marine  Diesels, 

Fulton  Machine  Co.,  31 

Mclntosh  &  Seymour,  28 

Midwest  Engine  Co.,  27    (see   Diesels, 
Werkspoor). 

Nelseco,  28    (see  Diesels,  New  London 
Ship.  &  Eng.  Co.) . 

New  York  Shipbuilding   Co.,   27    (see 
Diesels,  Werkspoor). 

Nobel  Bros.,  25 

Pacific. Skandia,  27 

Southwark-Harris,  22-25 

Werkspoor,  26-27 
Material,  foundation,  34-35 
McEwen  Diesel,  20-21 

admission  valves,  107-108 

air  compressor,  202-203 

bearings,  main,  50 

connecting-rod,  60 

cylinder,  Fig.  4 
head,  85 


,  McEwen  Diesel,  exhaust  valves,  107-108 
fuel  consumption,  251,  253,  259-260 

pump,  168-170 
guarantees,  251 
governor,  186-188 
indicator  cards,  273 
injection  valve,  145-146 
piston,  70 

valves,  admission  and  exhaust,  107-108 
camshaft,  108 
cam  clearances,  108 
timing,  109 
injection,  145-146 

timing,  109 

Mclntosh  &  Seymour  Diesel,  15-18 
admission  valves,  101 
air  compressor,  200-201 
connecting-rod,  60 
cylinder,  82-83 

head,  83 

exhaust  valve,  101 
efficiency,  255-256 
fuel  consumption,  251 

pump,  164-166 
governor,  189—193 
guarantee,  fuel,  251 
injection  valve,  139—142 
piston,  68-69 
production  costs,  263 
valves,  admission  and  exhaust,  101-104 
cam  clearance,  103 
camshaft,  102 
timing,  103 
injection,  139-142 

timing,  103 

Mclntosh  &  Seymour  Marine  Diesel,  28-29 
admission  valves,  115 
air  compressor,  199-200 
exhaust  valve,  115 
efficiency,  251 
fuel  consumption,  251 

pump,  166-168 
guarantee,  fuel,  251 
injection  valve,  139-142 
valves,  admission  and  exhaust,  115-118 
camshaft,  116 
operating  gear,  116-118 
reversing  gear,  116-118 
rocker  arms,  115 
injection,  139-142 
Midwest  Diesel,  27 


N 


National  Transit  Diesel,  20 

admission  valves,  108-110,  112 
air  compressor,  203 
bearings,  46 
connecting-rod,  60 
cylinder,  86 
head,  86 


466 


INDEX 


National     Transit    Diesel,    exhaust    valve, 

108-112 
efficiency,  251 
fuel  consumption,  251 
pump,  175-176 
pump,  1918  Model,  176-178 
guarantee,  fuel,  251 
governor,  186 
indicator  cards,  273,  275 
injection  valve,  149-150 
valves,  admission  and  exhaust,  108-112 
camshaft,  110,  112 
cam  clearance,  110 
timing,  110 
injection,  149-150 

timing,  110 

Nelseco  (New  London  Ship.  &  Eng.  Co.),  28 
admission  valves,  118 
connecting-rod,  62 
exhaust  valve,  118 
fuel  consumption,  251 

pump,  173-175 
guarantee,  fuel,  251 
.  reversing  gear,  118-119 
valves,  admission  and  exhaust,  118-119 

gear  for  reversing,  118-119 
Nordberg  Diesel  (Carels),  8 
Nobel  Bros.  Diesel,  Marine,  25 


Oil  engines, 

Brayton's,  2 

Diesel  (see  Diesel),  7-280 

Hornsby-Ackroyd,  3 

(see  also  Low-compression  engine). 
Low-compression,  306-459 

(see  Low-compression  index). 
Semi-Diesel     (see    Semi-Diesel   index), 

281-305 
Surface  Ignition,  306-459 

(see  Low-compression  index). 
Oil,  fuel,  234-250 
acid  in,  244 
ash  percentage,  244 
burning  point  of,  242 
classification  of,  234-238 
flash  point  of,  241 
gravity  of,  235 
heat  value,  239 
production  of,  235,  Table  IV 
residue  in,  240 
specification,  238 
sulphur,  percentage  of,  242 
viscosity  of,  244 
water  in,  243-244 
Oil  tanks,  244-248 
engine,  244-246 
storage,  246-248 
Oil,  tar,  248 

injection  valves  for,  154,  155,  249 


Oil,  method  of  burning,  248-250 
Otto  gas  engine,  2 
Otto's  Silent  engine,  3 


Pipe,  air,  206 

water,  214 
Piston  clearances,  65 

head  fracture,  75-76 
pin  bosses,  worn,  78 
pins,  emergency,  78 

grinding,  77-78 
rings,  74-75,  77 
Pistons,  designs  of,  64-72 

Allis-Chalmers,  69-70 
American  Diesel,  66-67 
Busch-Sulzer,  67-68 
Fulton  Machine  Co.,  Fig.  22 
Lyons-Atlas,  Fig.  23 
McEwen,  70 

Mclntosh  &  Seymour,  68-69 
National  Transit,  Fig.  73 
Nelseco,  Fig.  103         j 
Snow,  70 

Southwark-Harris,  Fig.  16 
Standard  Fuel  Oil,  70-72 
distorted,  67 
seized,  72-74 
types, 

crosshead,  65-66 
trunk,  65 
water-cooled,  68 
wear  of,  74 
Plant  buildings,  43 

logs,  268-269,  270 
Producer  gas  engine, 
Barber's,  1 

fuel  consumption,  265-266 
production  costs,  265 
Production  costs,  Diesel,  260-264,  265 
gas  engine,  264 
producer  gas  engine,  264-266 
steam  vs.  Diesel,  267 
turbine,  267 

Pumps,  fuel  (see  Fuel  pumps). 
circulating,  220 


Rigging,  indicator,  279 
Rings,  piston,  74-75,  77 


Schematic  layout  of  Diesel,  10 
Scored  shafts,  55-56 
Servomotor,  137-138 
Shafts,  centering  of,  40-43 

fractured,  56 

scored,  55—56 


INDEX 


467 


Snow  Diesel,  18-19 

admission  valves,  105-107 
air  compressor,  201-202 
bearings,  main,  46-47 
connecting-rod,  59 
cylinder,  Fig.  11,  83 

head,  83 

exhaust  valve,  105-107 
fuel  consumption,  251 
injection  valve,  142—144 
pump,  170-171 
guarantees,  fuel,  251 
governor,  185-186 
injection  valve,  142-144 
piston,  70 
valves,   admission   and   exhaust,    105— 

107 

camshaft,  106 
cam  clearances,  107 
timing,  107 
injection,  142-144 

timing,  107 

Southwark-Harris  two-cycle  Diesel,  22-25 
Standard  Fuel  Oil  two-cycle  Diesel,  25 
air  compressor,  203-204 

ports,  113-114 
connecting-rod,  Fig.  63 
cylinder,  80-81 

head,  81-82 
exhaust  ports,  113-144 
fuel  consumption,  251,  252 

pump,  178-179 
guarantee,  fuel,  251 
governor,  188 
indicator  cards,  274,  276 
injection  valve,  150-153 
piston,  power,  70-72 

scavenging,  72,  Fig.  63 
ports,  air,  113-114 
exhaust,  113-114 
valves,  injection,  150-153 

timing,  114 

Stud  nuts,  cylinder,  drawing  up,  89 
System,  Jahns,  governor,  183-186 

lubrication     (see    Lubricating    system), 

224-229 

Systems,   cooling   water    (see   Cooling  water 
systems),  209-223 


Tanks,  oil,  244-248 
water,  214 

Tar  oils,  154,  248-250 

injection  valves  for,  154,  249 
method  of  burning,  248-250 

Temperature  of  cooling  water,  211 

Template,  foundation,  34 

Timing  valve,  Diesel, 

American  Diesel,  97 
Busch-Sulzer,  99 


Timing  valve,  De  La  Vergne,  115 
McEwen,  109 
Mclntosh  &  Seymour,  103 
National  Transit,  110 
Snow,  107 

Standard  Fuel  Oil,  114 
method  of,  123-124 
Towers,  cooling,  216-220 
Two-stroke-cycle  Diesel,  22 
bearings,  56 
cycle  of  events,  13 
diagram  of,  13 
engine,  Clerk's,  5 
indicator  cards  from,  276 
Southwark-Harris,  22-25 
Standard  Fuel  Oil,  25 


Valve  cages,  119 

Valve,  fuel   pump    (see  Fuel  pumps),  159- 

180 

Valve  reamer,  121 
Valve  seats,  corrosion  of,  120-121 
Valves,  adjustments, 
cleaning  of,  121 
corrosion,  121 
grinding  of,  121-122 
leaks,  126 
timing,  123-124 
Valves,  admission  and  exhaust,  93-123 

Allis-Chalmers,  112 

American  Diesel,  94 

Busch-Sulzer,  98 

DeLa  Vergne,  115 

Fulton  Machine  Co.,  Fig.  22 

Lyons-Atlas,  Fig.  23 

McEwen,  107-108 

Mclntosh  &  Seymour,  101-104 

Mclntosh  &  Seymour  Marine,  116- 
118 

National  Transit,  108-112 

National  Transit  1918  Model,  111- 
112 

Nelseco,  118-119 

Snow,  105-107 

Standard  Fuel  Oil,  113-114 
Valves,  compressor,  205-206 
Valves,  fuel  injection,  classification, 

closed  type,  130-131 

open  type,  129 
Valves,  fuel  injection,  designs, 

Allis-Chalmers,  147-148 

American  Diesel,  131-134 

Busch-Sulzer,  134-139 

Fulton  Machine  Co.,  154 

Korting,  412-144 

McEwen,  145-146 

Mclntosh  &  Seymour,  139-142 

Mclntosh  &  Seymour,  Marine,  142 

National  Transit,  149-150 


468 


INDEX 


Valves,  fuel  injection,  designs,  Nelseco, 

Original  Diesel,  127 

Snow,  142-144 

Standard  Fuel  Oil,  150-153 
Valves,  water-cooled,  119-120 
Vibration  of  foundation,  36 

W 

Water,  bad,  58 

cooling,  amount  required,  55 


154         Water-cooled  valves,  119-120 

Water    cooling    systems    (see  Cooling  water 

systems),  209-223 
Water,      temperature      of      cooling,      211, 

Table  I 

Werkspoor  Marine  Diesel,  26-28 
Working  cycle  diagram  of  Diesel,  10-1 1 
Worthington   Pump    &    Mach.    Corp.    (see 

Snoiv  Diesel),  18-19 


Semi-Diesel  Engine  Index 


Air  compressor, 

De  La  Vergne  Type  F.  D.,  296 
Nordberg,  293 


Brons  (or  Hvid)  ignition,  282-288 
Burnoil  engine,  287 
Lyons-Atlas  V.  D.  H.,  284-288 
Midwest  V.  D.  H.,  284-288 
St.  Mary's  engine,  282-284 


Compression  pressure  of  Semi-Diesel  engine, 

280,  283,  298,  301 
Cup  ignition  (also  Hvid), 

Burnoil  Semi-Diesel,  287 

Midwest  V.  D.  H.,  284-288 

Miiller,  294-296 

Nordberg,  284-293 


Fuel  consumption, 

De  La  Vergne  Type  F.  H.,  299 

Midwest  V.  D.  H.,  287 

Price,  304 
Fuel  pumps, 

De  La  Vergne  Type  F.  H.,  299 

Lyons-Atlas,  287 

Midwest  V.  D.  H.,  287 

Nordberg,  290 


Governors, 

De  La  Vergne  Type  F.  H.,  300 
Midwest  V.  D.  H.,  286-287 
Nordberg,  290-293 


Hvid  ignition  device, 
Burnoil  engine,  287 
Midwest  V.  D.  H.,  engine,  284-288 
St.  Mary's  engine,  282-284 


De   La    Vergne   Type   F.    D. 

engine,  296-300 
fuel  consumption,  299 
fuel  pump,  299 
fuel  specification,  299 
ignition  device,  296-298 
indicator  cards,  281,  298 
valve  timing,  300 


Semi-Diesel        Ignition  devices, 

Brons  (or  Hvid),  282-288 

Burnoil,  287 

De  La  Vergne  Type  F.  H.,  296-298 

Midwest,  284-288 

Muller,  294-296 

Nordberg,  288-290 

Price,  301-305 


E 


Engines,  Semi-Diesel, 
Burnoil,  287 

De  La  Vergne  Type  F.  H.,  296-300 
Midwest  V.  D.  H.,  287 
Nordberg,  288-294 
Price,  301-305 
St.  Mary's,  282-284 


Lyons-Atlas    (Midwest)    Semi-Diesel     284- 

288 


M 

Mean  effective  pressure, 

Midwest  V.  D.  H.,  287 
Price,  305 


INDEX 


469 


Midwest    V.    D.    H.    Semi-Diesel    engine, 

284-288 
Muller  ignition  device,  294-296 

N 

Nordberg  Semi-Diesel,  288-293 
frame,  293 
fuel  pump,  290 
governor,  290-293 
ignition  device,  288-290 
injection  timing,  293 


Semi- Diesel  engine,  De  La  Vergne,  296-300 
Midwest,  284-287 
Nordberg,  288-294 
Price,  301-305 
St.  Mary's,  282-284 


Two-stroke-cycle  Semi-Diesel  engines, 
indicator  card  of,  281 
JSfordberg  engine,  288-294 


Price  ignition  system,  301-305 
atomizer,  301 
fuel  consumption,  304 
indicator  card,  304 
test  by  U.  S.  Navy,  305 


Semi-Diesel  engine,  281-305 
Burnoil,  287 


Valve  timing, 

De  La  Vergne  Type  F.  H.,  300 
Nordberg,  293 

W 

Water  injection, 

Nordberg  engine,  294 


Low-Compression  Engine  Index 


Air  seal  for  crankshaft, 354-357 

emergency,  355-356 

Fairbanks-Morse,  355 

Mietz  &  Weiss,  355,  Fig.  280 

open  frame  engines,  on,  356-357 
Air  starting  systems,  432-434 

Fairbanks-Morse,  433-434 

Mietz  &  Weiss,  434 

Primm,  434 
Air-suction  valves,  351-354 

Bessemer,  353-354 

Fairbanks-Morse,  351-352 

Mietz  &  Weiss,  352-353 

Muncie,  352 

B 

Babbitting  crank-pin  bearing,  343-344 
Bearings,  main,  357-361,  Figs.  282-285 
Bessemer  oil  engine, 

air-suction  valve,  353-354 

behavior  on  various  fuels,  450 

connecting-rod,  340,  Fig.  265 

frame,  348 

fuel  consumption,  452-453 
injection  nozzle,  408 
pump,  393-397 

fuel  injection  pump,  393-397 

governor,  392-397 

ignition  device,  321 

piston,  Fig.  340. 

water  injection  system,  418-419 


Bolinder  oil  engine, 

cylinder,  326 

ignition  device,  318 
Brasses,  connecting-rod,  342 
Bridges,  exhaust,  338 
Buckeye-Barrett  oil  engine, 

fuel  consumption,  454 

fuel  injection  nozzle,  406-407 

fuel  injection  pump,  402 

governor,  402 

ignition  device,  320-321 

piston,  333 


Chicago    Pneumatic    Tool    Co.,    Giant    oil 
engine, 

frame,  Fig.  252 

fuel  injection  pump,  390 

governor,  389-390 

ignition  device,  314-316 

injection  nozzle,  403-404 

water  injection  system,  418 
Clearances,  crank-pin,  344 

piston,  334-335 

pins,  339 

Combustion,  theory  of,  307-309 
Compression    pressure  of   low-compression 

engines,  306-307 
Connecting-rod,  adjustments,  341-342 

babbitting  brass,  343-344 

brasses,  342-343 


470 


INDEX 


Connecting-rods,  designs, 

Bessemer,  340,  Fig.  265 

Buckeye-Barrett,  340,  Fig.  266 

De  La  Vergne,  341,  Fig.  261 

Fairbanks-Morse,    Type    Y,    341,  Fig. 
269 

Muncie,  340-341,  Fig.  268 

Primm,  340 
Constant   injection   angle   governors,    390- 

392 

Costs,  operation,  455-459 
Crank-pin  clearances,  344 

lubrication,  344-346 

babbitting  bearing  of,  343-344 
Crankshaft,  361-362 
Crosshead  piston  design,  349-350 
Cylinder  design,  324-332 

four-stroke-cycle  engine,  325 

thickness  of  walls,  326 

two-stroke-cycle  engine,  324-327 
Cylinder,  fractured,  329-331 

reboring  of,  327-328 

wear  of,  328-329,  413 
Cylinder-head  packing,  331 


De    La    Vergne    D.H.    low-pressure    oil 

engine,  307 

bearings,  main,  Fig.  282 
connecting-rod,  341,  Fig.  261 
cylinder,  325 
fuel  consumption,  454 

injection  pump,  400-401 
governor,  400-401 
ignition  device,  321-322 
piston,  333,  Fig.  261 

-pin  lubrication,  345,  Fig.  261 
Design  of  ignition  device,  306-323 
Distributor  for  Mietz  &  Weiss  fuel    pump, 
385-387 


Engine  pounds,  441 

smokes,  438-439 
Exhaust  bridges,  distorted,  338 

pipe,  420-422 

pits,  422-425 


Fairbanks-Morse  Horizontal  Type  Y  engine, 
air  seal  for  crankshaft,  355 
-suction  valve,  351-352 
behavior  on  various  fuels,  449 
frame,  348 
fuel  injection  nozzles,  405-406 

pump,  374-376 
governor,  372-374 
ignition  device,  316-318 
piston,  333,  Fig.  260 
pin  lubrication,  344-345 


Fairbanks-Morse  Vertical  Type  Y  oil  engine, 
air  seal  for  crankshaft,  355 
-starting  system,  432-434 
-suction  valve,  351-352 
connecting-rod,  341,  Fig.  269 
cylinder,  326 
fuel  consumption,  454 

injection  pump,  377-381 
governor,  377-380 
ignition  device,  318-320 
Flywheels,  362-364 

puller,  363-364,  Figs.  286-287 
Fractured  cylinders,  329-331 
Frames,  347-351 

inclosed  type,  347-348 
Bessemer,  348 

Fairbanks-Morse,  348,  Fig.  253 
Mietz  &  Weiss,  348 
Muncie,  Fig.  251 
open  type,  348-351 
Buckeye-Barrett,  349 
De  La  Vergne,  348 
Giant,  Fig.  252 
Fuel,  447-455 

behavior   of  engines   on   various  fuels, 

449-450 

specifications,  448 
storage  of,  450-451 
Fuel  consumption,  451-455 
Bessemer,  452-453 
Buckeye-Barrett,  454 
De  La  Vergne,  454 
Fairbanks-Morse,  453 
Fetter,  454 
usual  guarantees,  451 
Fuel  injection  nozzles,  403-410 
care  of,  409-410 
designs, 

Bessemer,  408 

Buckeye-Barrett,  406-407       , 

Fairbanks-Morse,  405-406 

Giant     (Chicago     Pneumatic     Tool 

Co.),  403-405 
Mietz  &  Weiss,  408-409 
Muncie,  404-405 
Primm,  407-408 
Fuel  injection  pumps, 
Bessemer,  393-397 
Buckeye-Barrett,  402 
De  La  Vergne,  400-401 
Fairbanks-Morse  [Horizontal  Type  Y, 

374-376 
Fairbanks- Morse  (Vertical  [Type    Y, 

377-381 
Giant  (Chicago  Pneumatic  Tool  Co.), 

390 

Mietz  &  Weiss  Horizontal,  381-382 
Mietz  &  Weiss  Vertical,  384-385 

distributor  for,  385-387 
Muncie,  369-371 
Muncie  large  engines,  371 
Fuel  injection  pump  regulators,  387-389 


INDEX 


471 


Governors,  365-402 

constant  injection  angle,  390-392 
designs  of, 

Bessemer,  392-397 
Buckeye-Barrett,  402 
De  La  Vergne,  400-401 
Fairbanks-Morse    Horizontal    Type 

Y,  372-374 
Fairbanks-Morse   Vertical   Type   Y, 

377-380 
Giant  (Chicago  Pneumatic  Tool  Co.), 

389-390 

Mietz  &  Weiss  Horizontal,  381-382 
Mietz  &  Weiss  Vertical,  383-384 
Muncie,  366-369 

Governors,  "Hit  &  Miss,"  365-366 
Governors,  Quantitative,  366 

H 

Head,  cylinder,  packing,  331-332 
Head,  piston,  338-339 
Hornsby-Ackroyd  oil  engine,  6,  307 


Ignition  devices,  309-323 

hot-ball,  Muncie,  309-313 

hot-plate,   Giant   (Chicago  Pneu.   Tool 

Co.),  314-316 
hot-tube,  Primm,  313-314 
separate  combustion,  316 
Bessemer,  321 
Bolinder,  318 
Buckeye-Barrett,  320 
De  La  Vergne,  321-322 
Fairbanks-Morse,  316-320 
Petter,  318 

Indicator  cards,  442-446 
De  La  Vergne,  442 
Fairbanks-Morse,  443 
Mietz  &  Weiss,  444-445 
Muncie,  444 
Primm,  445 
Injection,  water,  410-413 


Low-compression  oil  engines,  306-459 
Lubrication,  amount  of,  437-438 

crank  pin,  344-346 

piston  pin,  344-346 


M 


Method   of  operation,  low-compression  oil 
engine,  307 

Mietz  &  Weiss, 

air  suction,  352-353 
crank-pin  lubrication,  344-346 


Mietz  &  Weiss,  crankshaft  air  seal,  354 
cylinder,  326 
frame,  348 

fuel  injection  nozzle,  408-409 
pump,  382-383,  384-385 

distributor,  385,  387 
governor  for  small  engines,  381-382 
piston-pin  lubrication,  344-346 
water  injection  system,  414-416 

Muncie  oil  engine, 

air-starting  system,  434 
air-suction  valve,  352 
bearing,  main,  360,  Fig.  285 
connecting-rod,  341,  Fig.  268 
crankshaft  air  seal,  Fig.  285 
fuel  injection  nozzle,  404-405 
pump,  369-371 

for  large  engines,  371 
governor,  366-369 
ignition  device,  309-313 
piston,  333 
water  injection  system,   416-417 


Nozzles,  fuel  injection,  403-410 
Bessemer,  408 
Buckeye-Barrett,   406-407 
Fairbanks-Morse,  405-406 
Giant     (Chicago    Pneumatic    Tool 

Co.),  403-404 
Mietz  &  Weiss,  408,  409 
Muncie,  404-405 
Primm,  407-408 


O 


Operation,  costs,  455-459 
engine  pounds,  441 
indicator  cards,  442-446 

De  La  Vergne,  442 

Fairbanks-Morse,  443 

Mietz  &  Weiss,  444-445 

Muncie,  444 

Primm,  445 
lubrication,  437 

method    of,    in   low-compression    en- 
gines, 307 

preignition,  439-441 
smoking  engine,  438 
starting  an  engine,  435-437 
stopping  engine,  441-442 
temperature  of  cooling  water,  437 


Packing,  cylinder  head,  331-332 
Piston  clearances,  334-335 
Piston  heads,  fractured,  338-339 
Piston-pin  lubrication,  344-345 
Piston  pins,  339 


472 


INDEX 


Piston  rings,  337 

Pistons,  crosshead  design,  349-351 
distorted,  336-337 
turning  of  new,  335-336 
Pistons,  types  of,  333-335 

Buckeye-Barrett,  333-334 
De  La  Vergne,  333 
Muncie,  333 
with  deflector  lips,  333 
Preignitions,  439-441 
Primm  oil  engine, 

air-starting  system,  434 
bearings,  main,  Fig.  283 
connecting-rod,  341,  Fig.  267 
fuel  injection  nozzle,  407-408 

pump,  399-100 
governor,  397-399 
ignition  device,  313-314 
water  injection  system,  418 


R 

Reboring  of  cylinder,  327-328 
Regulators,  fuel  pump,  387-389 
Rings,  piston,  337 


S 


Smoky  engine,  438-439 
Specifications  of  fuel  oil,  448-449 
Starters,  air,  432-434 
Starting  an  engine,  435-437 
Stopping  the  engine,  441-442 


Temperature  of  cooling  water,  437 
Theory    of     combustion,     low-compression 

engine,  307-309 
Two-stroke-cycle  low-compression    engine, 

307 

ignition  devices,  309 
hot-ball,  309-313 
hot-plate,  314-316 
hot-tube,  313-314 
separate   combustion   chamber,  316- 

321 

method  of  operation,  307 
theory  of  combustion,  307-309 


W 


Water  circulating  systems,  425-431 
fresh  water  system,  .427-429 
tank  and  tower  system,  429-431 
thermo-syphon  system,  425-427 
Water  injection,  410-413 

cylinder  wear  due  to,  413 
faulty  lubrication  due  to,  413-414 
method  of,  414-419 
Bessemer,  418-419 
bleeder  valve,  414 
Giant  (Chicago  Pneumatic  Tool  Co.), 

418 

Mietz  &  Weiss,  414-146 
Muncie  automatic  pump,  416-417 
Muncie  Standard,  416 
Wear  in  cylinder  walls,  328-329 


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